Fix Android release build and verify on emulator

- Disable Kotlin incremental compilation (kotlin.incremental=false): the
  project lives on D: while Gradle's Kotlin daemon caches default to C:,
  which crashes with "this and base files have different roots" when
  closing incremental caches.
- Drop flutter_map_tile_caching for now: it pins objectbox_flutter_libs
  ^4.1.0, which fails checkReleaseAarMetadata against newer AndroidX
  transitive deps (needs compileSdk 34+, itself built against android-31).
  Not used in code yet, so deferred rather than forcing an unverified
  dependency_override.
- Add web/ platform for fast local UI iteration without an emulator.
- Ignore .claude/ (Claude Code session state, not project content).

Verified: flutter analyze, flutter test, and a real release build running
on a newly created Pixel_10a-profile Android emulator (API 36).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/android/gradle.properties

@@ -1,5 +1,11 @@
 org.gradle.jvmargs=-Xmx8G -XX:MaxMetaspaceSize=4G -XX:ReservedCodeCacheSize=512m -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
+# Projekt liegt auf D:, Gradle/Kotlin-Nutzerverzeichnis standardmaessig auf C: -
+# Kotlins inkrementeller Compiler bricht beim Schliessen der Caches ab, wenn
+# Projekt- und Cache-Pfad auf unterschiedlichen Laufwerken liegen ("this and
+# base files have different roots"). Inkrementelle Kotlin-Kompilierung daher
+# deaktiviert (etwas langsamere Rebuilds, aber stabil).
+kotlin.incremental=false
 # This newDsl flag was added by the Flutter template
 android.newDsl=false
 # This builtInKotlin flag was added by the Flutter template