fix: re-land peek-to-thread handoff with callback pattern (#1464)

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s

[CraigBuckmaster]

Closes#1464.

Re-lands the FAB peek → Amicus tab handoff that was originally shipped in PR #1500 and reverted in #1503 due to the iOS 26 TurboModule crash on TestFlight build (12). The underlying crash mechanism (ObjCTurboModule::performVoidMethodInvocation at RCTTurboModule.mm:441 → __cxa_rethrow → abort) was independently patched by app/patches/react-native+0.81.5.patch (already on master as part of the iOS 26 workaround triangle), so the specific (12) symptom cannot reoccur with the current build configuration.

What changed vs. the original PR

The original promotePeekToAmicusThread called navigation.getParent().navigate('AmicusTab', ...) from inside the service layer. That coupled a leaf component to the tab name and the navigator tree shape — the exact anti-pattern that motivated #1562 / #1563 (now subsumed into this card).

The re-land introduces a clean callback pattern:

• Service returns a navigation-agnostic PromotePeekResult discriminated union: { kind: 'existing', threadId, ... } or { kind: 'new', promotedMessages, ... }. Zero React Navigation imports.
• AmicusFab accepts an optional onContinueInTab(result) prop. When the parent provides it, the FAB delegates navigation entirely. When absent (e.g. a test mounting AmicusFab directly), the FAB falls back to internal navigation — defensive, keeps the component usable in isolation.
• App.tsx provides the concrete navigation via navigationRef. This is now the single call site that knows about 'AmicusTab', 'Thread', and 'NewThread' screen names. If navigators are restructured, only this file changes.

File summary

File	Change
app/src/services/amicus/promotePeekToThread.ts	NEW — navigation-agnostic service
app/src/services/amicus/__tests__/promotePeekToThread.test.ts	NEW — 7 cases, no nav mocks
app/src/services/amicus/studyLaunch.ts	Removed deprecated promotePeekToAmicusThread + unused imports
app/src/services/amicus/__tests__/studyLaunch.test.ts	Dropped the two cases now covered in the new test file
app/src/services/amicus/index.ts	Export rename
app/src/components/amicus/AmicusFab.tsx	New onContinueInTab? prop; internal nav as defensive fallback
app/App.tsx	Provides handleAmicusContinueInTab via navigationRef

Thread-lookup logic (linked question → linked session → latest chapter thread) is preserved verbatim from the previous implementation. Only the navigation side-effect moves out of the service.

Verification

• tsc --noEmit: clean (0 errors)
• jest src/services/amicus/__tests__/promotePeekToThread.test.ts src/services/amicus/__tests__/studyLaunch.test.ts: 9/9 pass
• Broader sweep jest src/services/amicus src/components/amicus: 235/236 pass; the one failure is a pre-existing flaky afterEach timeout in AmicusPeekSheet.test.tsx that passes cleanly when run in isolation (5/5)
• eslint: 0 errors on changed files

Rollback plan

If this re-introduces a crash on TestFlight, the rollback is mechanical:

1. git revert <merge-commit> on master
2. The reverted state restores promotePeekToAmicusThread in studyLaunch.ts, the AmicusFab original handleContinueInTab, and removes the new files
3. No data migrations or persisted-state changes are involved — this is a pure refactor of the in-process control flow

The FAB's defensive internal-navigation fallback also means that if App.tsx callback wiring is ever lost (e.g. a stray refactor strips the prop), the feature still works — it just isn't architecturally clean.

What still belongs to the epic

With this merged and verified on TestFlight, all 27 child issues of Epic #1446 are complete and the epic can be closed.

[github-actions]

Test Results

✅ All tests passed

	Passed	Failed	Total
Tests	✅ 3962	❌ 0	3962
Suites	✅ 529	❌ 0	529

Coverage

Statements	Branches	Functions	Lines
—	—	—	—

⏱️ Duration: 94.4s