Virtualize the native Qt conversation view

.github/workflows/ci.yml

@@ -32,11 +32,11 @@ jobs:
             ${{ github.event_name == 'pull_request' &&
                 github.event.pull_request.head.sha || github.sha }}
 
-      - name: Check out pinned SNode.C
+      - name: Check out SNode.C head
         uses: actions/checkout@v5
         with:
           repository: SNodeC/snode.c
-          ref: 212bd4f8a16637405ab850a52adb9da8555dca3d
+          ref: master
           path: _deps/snodec
 
       - name: Check out paired AISuite Codex

CMakeLists.txt

@@ -60,6 +60,7 @@ set(
     src/codex/GitDiffProvider.h
     src/codex/FileSelectionDialog.cpp
     src/codex/FileSelectionDialog.h
+    src/codex/ForkNaming.h
     src/codex/MainWindow.cpp
     src/codex/MainWindow.h
     src/codex/NewThreadDialog.cpp
@@ -89,6 +90,12 @@ set(
     src/codex/middle/ComposerPane.h
     src/codex/middle/ConversationCards.cpp
     src/codex/middle/ConversationCards.h
+    src/codex/middle/ConversationPresentation.cpp
+    src/codex/middle/ConversationPresentation.h
+    src/codex/middle/ConversationHeightIndex.cpp
+    src/codex/middle/ConversationHeightIndex.h
+    src/codex/middle/ConversationItemModel.cpp
+    src/codex/middle/ConversationItemModel.h
     src/codex/middle/ConversationView.cpp
     src/codex/middle/ConversationView.h
     src/codex/middle/InspectorPane.cpp
@@ -191,8 +198,14 @@ if(BUILD_TESTING)
         src/codex/ui/NodeGraphUiAdapter.h
         src/codex/middle/ConversationCards.cpp
         src/codex/middle/ConversationCards.h
+        src/codex/middle/ConversationPresentation.cpp
+        src/codex/middle/ConversationPresentation.h
         src/codex/middle/ConversationView.cpp
         src/codex/middle/ConversationView.h
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
         src/codex/middle/MiddleTypes.cpp
         src/codex/middle/MiddleTypes.h
         src/codex/ui/UiStyle.cpp
@@ -334,8 +347,14 @@ if(BUILD_TESTING)
         tests/codex/ConversationCardsTest.cpp
         src/codex/middle/ConversationCards.cpp
         src/codex/middle/ConversationCards.h
+        src/codex/middle/ConversationPresentation.cpp
+        src/codex/middle/ConversationPresentation.h
         src/codex/middle/ConversationView.cpp
         src/codex/middle/ConversationView.h
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
         src/codex/middle/MiddleTypes.cpp
         src/codex/middle/MiddleTypes.h
         src/codex/ui/UiStyle.cpp
@@ -357,6 +376,101 @@ if(BUILD_TESTING)
         PROPERTIES TIMEOUT 35 ENVIRONMENT "QT_QPA_PLATFORM=offscreen"
     )
 
+    qt_add_executable(
+        codexui-conversation-item-model-test
+        tests/codex/ConversationItemModelTest.cpp
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
+        src/codex/middle/MiddleTypes.cpp
+        src/codex/middle/MiddleTypes.h
+    )
+    target_compile_features(
+        codexui-conversation-item-model-test PRIVATE cxx_std_20
+    )
+    target_include_directories(
+        codexui-conversation-item-model-test PRIVATE src
+    )
+    target_link_libraries(
+        codexui-conversation-item-model-test
+        PRIVATE codexui-nodegraph Qt6::Widgets
+    )
+    add_test(
+        NAME codexui-conversation-item-model
+        COMMAND codexui-conversation-item-model-test
+    )
+    set_tests_properties(
+        codexui-conversation-item-model
+        PROPERTIES TIMEOUT 15
+    )
+
+    qt_add_executable(
+        codexui-conversation-virtualization-test
+        tests/codex/ConversationVirtualizationTest.cpp
+        src/codex/middle/ConversationCards.cpp
+        src/codex/middle/ConversationCards.h
+        src/codex/middle/ConversationPresentation.cpp
+        src/codex/middle/ConversationPresentation.h
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
+        src/codex/middle/ConversationView.cpp
+        src/codex/middle/ConversationView.h
+        src/codex/middle/MiddleTypes.cpp
+        src/codex/middle/MiddleTypes.h
+        src/codex/ui/UiStyle.cpp
+        src/codex/ui/UiStyle.h
+    )
+    target_compile_features(
+        codexui-conversation-virtualization-test PRIVATE cxx_std_20
+    )
+    target_include_directories(
+        codexui-conversation-virtualization-test PRIVATE src
+    )
+    target_link_libraries(
+        codexui-conversation-virtualization-test
+        PRIVATE codexui-nodegraph Qt6::Widgets
+    )
+    add_test(
+        NAME codexui-conversation-virtualization
+        COMMAND codexui-conversation-virtualization-test
+    )
+    set_tests_properties(
+        codexui-conversation-virtualization
+        PROPERTIES TIMEOUT 20 ENVIRONMENT "QT_QPA_PLATFORM=offscreen"
+    )
+
+    qt_add_executable(
+        codexui-conversation-view-benchmark
+        tests/codex/ConversationViewBenchmark.cpp
+        src/codex/middle/ConversationCards.cpp
+        src/codex/middle/ConversationCards.h
+        src/codex/middle/ConversationPresentation.cpp
+        src/codex/middle/ConversationPresentation.h
+        src/codex/middle/ConversationView.cpp
+        src/codex/middle/ConversationView.h
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
+        src/codex/middle/MiddleTypes.cpp
+        src/codex/middle/MiddleTypes.h
+        src/codex/ui/UiStyle.cpp
+        src/codex/ui/UiStyle.h
+    )
+    target_compile_features(
+        codexui-conversation-view-benchmark PRIVATE cxx_std_20
+    )
+    target_include_directories(
+        codexui-conversation-view-benchmark PRIVATE src
+    )
+    target_link_libraries(
+        codexui-conversation-view-benchmark
+        PRIVATE codexui-nodegraph Qt6::Widgets
+    )
+
     qt_add_executable(
         codexui-application-layout-test
         tests/codex/EstablishedUiUxTest.cpp
@@ -376,8 +490,14 @@ if(BUILD_TESTING)
         src/codex/middle/ComposerPane.h
         src/codex/middle/ConversationCards.cpp
         src/codex/middle/ConversationCards.h
+        src/codex/middle/ConversationPresentation.cpp
+        src/codex/middle/ConversationPresentation.h
         src/codex/middle/ConversationView.cpp
         src/codex/middle/ConversationView.h
+        src/codex/middle/ConversationHeightIndex.cpp
+        src/codex/middle/ConversationHeightIndex.h
+        src/codex/middle/ConversationItemModel.cpp
+        src/codex/middle/ConversationItemModel.h
         src/codex/middle/InspectorPane.cpp
         src/codex/middle/InspectorPane.h
         src/codex/middle/MiddleRegionWidget.cpp

docs/native-ui-ux-qualification-inventory.md

@@ -42,7 +42,7 @@ child, partial order, or intermediate lifecycle style.
 
 | Area | Situations and expected result | Qualification |
 | --- | --- | --- |
-| Main window | Initial show, maximize/restore, resize, splitter drag, pane hide/show, minimum useful size | No clipped controls, oscillating layout requests, stale overlay geometry, or whole-window repaint from a descendant update |
+| Main window | Initial show, maximize/restore, resize, splitter drag, pane hide/show, minimum useful size | No clipped controls, oscillating layout requests, stale overlay geometry, or whole-window repaint from a descendant update; splitter widths track immediately, conversation reflow is frame-bounded, and release settles exactly |
 | Top chrome | Connection label/dot/menu, controller button, request indicator, restore-pane buttons | Setters/style polish/paint occur only when the effective displayed value changes; item streaming does no work here |
 | Bottom status | Ready/connecting/disconnected/error and attribution | Stable geometry; exact state/tone; unrelated thread changes do not repaint it |
 | Conversation chrome | Selected-thread title, workspace, last activity, lifecycle state and visibility/filter buttons | Only changed effective fields update; item text streaming does not rewrite thread chrome; final status is immediate |
@@ -63,9 +63,9 @@ with fixed screen geometry and pixel-difference regions.
 | Rows | Name/preview/ID fallback, status dot, hover, selected state, badges/tooltips and exact canonical state vocabulary match the legacy appearance |
 | Selection | Left click changes selection once; background activity never steals it; selecting a child keeps its root visible; removal clears selection safely |
 | Hierarchy | Root/child ownership, expansion/collapse, deep indentation, late parent, fork reassignment and child removal retain complete reachable topology |
-| Sorting | Recent, Created, Last changed and natural Alphanumeric orders; missing timestamps; local prompt ticks; non-sort field changes never scan/reorder |
-| Local draft row | New Thread insertion, animation, promotion to provider ID, failure, abandon-empty, second-create guard and later-navigation preservation use one stable row |
-| Context menu | Right-click targets the pointed row without selection, holds hover while open, dismisses without click-through, and exposes correct reload/rename/fork/archive/delete state |
+| Sorting | Exactly Alphanumeric, Created, and Recent; natural-number titles; newest-first timestamps; missing timestamps last; fast DB-only first page, automatic background file reconciliation, cursor-guarded near-end paging; Recent admission promotion, acknowledgement confirmation, rejection rollback, and criterion-specific re-sorting |
+| Local draft row | New Thread insertion, chosen-name preservation, prompt-bound animation, promotion to provider ID, failure, abandon-empty, second-create guard and later-navigation preservation use one stable row |
+| Context menu | Right-click targets the pointed row without selection, holds hover while open, dismisses without click-through, and exposes correct reload/rename/Quick fork/Fork with options/archive/delete state; advanced fork fields and hierarchical chosen names reach the exact action |
 | Incremental update | Name/status/tooltips patch only the affected row and repaint only its rectangle; no whole-list update suppression |
 | Atomic topology | Insert/remove/reparent/reorder computes a complete target before commit and never exposes partial ordering |
 | Large list | Visible rows plus two-row overscan only; bounded scans complete under unrelated revisions; scroll position and expansion remain stable |
@@ -135,7 +135,10 @@ For each type verify:
   direction, title anchoring, keyboard focus and no geometry change for
   paint-only state;
 - Copy availability, exact plain/Markdown content, 0.5-second check feedback,
-  reduced-motion behavior, overlay placement and no header movement;
+  reduced-motion behavior, overlay placement, uniformly narrow phase-to-Copy
+  spacing and no header movement;
+- authored single newlines remain visible in normal and steering You cards
+  while copied Markdown, blank lines, and fenced code remain exact;
 - retained text truncation notice and copied disclosure at the byte bound;
 - attachment order, encoded filenames, bounded image ribbon, horizontal
   scrolling without vertical growth, missing-image accessibility and modeless