Implement Phase 1: project skeleton and data layer

Android project with Kotlin, Jetpack Compose, and Room. Includes:
- Gradle build system with version catalog, foojay JDK resolver, lint config
- Room entities (Notebook, Page, Stroke) with packed float BLOB encoding
- DAOs and repositories for all entities
- Unit tests for blob roundtrip and PageSize enum (10 tests, all passing)
- Minimal Application class and stub MainActivity

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.2-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists