chore: enable R8 optimised resource shrinking and guard it

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)

[code418]

Summary

• Remove the dead android.enableR8=true flag from gradle.properties (AGP has had it Enforced since 7.0 and warns to delete it).
• Enable android.r8.optimizedShrinking=true — AGP 8.11's name for R8 optimised resource shrinking (prerequisites integratedResourceShrinking + nonFinalResIds already default true).
• Assert in app/build.gradle that the release build type stays minifyEnabled + shrinkResources, so the implicit Flutter default can't silently regress.

Why

Android Studio surfaced a prompt to "Enable app optimization with R8". Investigation showed R8 code + resource shrinking is already on — the Flutter Gradle plugin enables it for release by default (minify{Phone,Auto,Wear}ReleaseWithR8 all run; mapping.txt shows R8 8.11.18 with 450k renamed symbols; full mode + integrated resource shrinking both default on). So the real gaps were: an obsolete no-op flag that misleads readers about where the switch lives, the one remaining opt-in the docs call out, and nothing in-repo pinning the behaviour.

The IDE quick-fix for that prompt inserts the AGP 9.3+optimization { enable = true } DSL, which does not exist on our AGP 8.11.1 (Optimization has no enable property until 9.3) and fails at configuration time — this PR uses the correct 8.11 path instead.

Design spec: docs/superpowers/specs/2026-07-24-r8-app-optimization-design.md.

Note: R8 only optimises the Java/Kotlin layer; the Dart code in libapp.so is untouched (--obfuscate is a separate, out-of-scope lever).

Test plan

• flutter build appbundle --flavor phone --release builds clean (assertion passes, R8 runs)
• flutter build appbundle --flavor wear --release -t lib/main_wear.dart builds clean
• flutter build apk --flavor auto --release -t lib/main.dart builds clean
• Release AAB/APK sizes hold or shrink vs baseline (no regression from optimised shrinking)
• phone release APK on emulator: launch, login, Nearby map, James strip, claim quiz, History, About all render (no missing shrunk resources)
• Sanity: a build with -Pshrink=false now fails with the R8-optimised assertion (guard works)