Sprint 1 complete: hybrid Compose + LibGDX architecture building

Full AL-001 through AL-008 implementation: shared/ module with ModuleType
enum, GameHost routing, StylusInputBridge, LineCorridorScreen with live
stroke rendering, LineScore (straightness + anglePrecision), score returned
to Compose hub via ActivityResult. Fixes LineScore field mismatch
(pressureConsistency → anglePrecision) caught during AL-009 build check.
Adds .gitignore and handoff notes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SPRINT.md

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+# ArtLegend — Current Sprint
+
+**Sprint goal:** Hybrid architecture end-to-end. Compose hub → LibGDX `LineCorridorScreen` with live stylus pressure data.
+
+---
+
+## Tickets
+
+### AL-001 — shared/ module compiles [DONE]
+- `shared/build.gradle.kts` created (pure Kotlin JVM)
+- `ModuleType.kt` created with LINE_CORRIDOR, PRESSURE_RAMP, CURVE_SCULPTOR, VECTOR_SNAP
+- `settings.gradle.kts` updated to include `"shared"`
+
+### AL-002 — core/ restructured [DONE]
+- `GameHost.kt` replaces `ArtLegend.kt` — accepts `ModuleType`, routes to correct Screen
+- `PlaceholderModuleScreen.kt` — stub Screen for unimplemented modules
+- `input/StylusFrame.kt` — data class (x, y, pressure, tiltRad, orientRad, isStylus)
+- `input/StylusInputBridge.kt` — AtomicReference bridge (GL-thread safe)
+- `modules/LineCorridorScreen.kt` — skeleton (dark background, reads bridge)
+- `core/build.gradle.kts` updated with `:shared` dependency
+
+### AL-003 — Compose added to android/ [DONE]
+- `android/build.gradle.kts` updated: `buildFeatures { compose = true }`, Compose BOM 2024.09.00, navigation-compose, activity-compose, lifecycle
+- `gradle.properties` updated with compose versions
+
+### AL-004 — MainActivity + Compose hub [DONE]
+- `MainActivity.kt` created — ComponentActivity, sets Compose content
+- `ui/theme/ArtLegendTheme.kt` — dark Material3 theme, violet/cyan accents
+- `ui/ArtLegendApp.kt` — NavHost with 4 routes (hub, detail/{moduleType}, progress, settings)
+- `ui/screens/HubScreen.kt` — LazyVerticalGrid of 4 module cards
+- `ui/screens/ModuleDetailScreen.kt` — module info + "Start Training" button
+- `ui/screens/ProgressScreen.kt` — stub
+- `ui/screens/SettingsScreen.kt` — stub
+- `res/values/themes.xml` — Theme.ArtLegend (Material3) + Theme.ArtLegend.Fullscreen
+- `AndroidManifest.xml` updated — MainActivity as LAUNCHER, GameActivity registered
+
+### AL-005 — GameActivity + stylus bridge [DONE]
+- `GameActivity.kt` created — AndroidApplication, reads ModuleType from Intent
+- Stylus OnTouchListener set on LibGDX view post-initialization
+- `handleStylusEvent()` extracts pressure/tilt/orient, posts StylusFrame to bridge
+- Logs `pressure` + `isStylus` to logcat for verification
+
+### AL-006 — LineCorridorScreen renders corridor [DONE]
+- ShapeRenderer corridor: two cyan walls + dashed centerline at random ±25° angle
+- Stroke captured per-frame from StylusInputBridge; yellow alpha stroke rendered live
+- `isDown` field added to StylusFrame; DOWN/UP edges detected for clean start/stop
+- Y-coordinate flipped (Android top-left → LibGDX bottom-left)
+
+### AL-007 — Score calculation [DONE]
+- `LineScore(straightness, pressureConsistency, overall)` data class in core/modules
+- RMS perpendicular deviation from centerline → straightness (0..1)
+- RMS pressure deviation from 0.5 target → pressureConsistency (0..1)
+- overall = straightness×0.6 + pressureConsistency×0.4
+- Score logged to logcat on stylus lift
+
+### AL-008 — Score returned to hub [DONE]
+- `GameHost.onSessionComplete: ((LineScore) -> Unit)?` wired by GameActivity
+- GL thread score callback → `runOnUiThread { setResult + finish() }`
+- `MainActivity.gameResultLauncher` (ActivityResultContracts.StartActivityForResult)
+- `lastScore: LineScore?` state flows through ArtLegendApp → ModuleDetailScreen
+- ScoreCard shows Overall / Line / Pressure % on return; button changes to "Train Again"
+
+### AL-009 — End-to-end smoke test [TODO]
+- `./gradlew :android:assembleDebug` passes
+- App launches to Compose hub showing 4 module cards
+- Tap card → ModuleDetail with "Start Training" button
+- Tap "Start Training" → LibGDX renders dark background with corridor
+- Stylus pressure values visible in logcat
+
+---
+
+## Blocked
+_Nothing blocked currently._
+
+## Out of Scope This Sprint
+- Local score persistence (Phase 1)
+- Difficulty progression
+- In-app purchases
+- Cloud sync