fix(fdroid): drop Google Play Core so the scanner accepts the APK; prep v0.1.15

F-Droid's APK scanner rejected v0.1.14: 6 com.google.android.play.core.*
(SplitInstall/SplitCompat/tasks) references. They came from Flutter's
io.flutter.embedding.engine.deferredcomponents.PlayStoreDeferredComponentManager
being pinned by our over-broad '-keep class io.flutter.** { *; }' ProGuard
rule — Tane uses no deferred components, so R8 should shrink that manager
away (as it does for immich and other Flutter F-Droid apps, which don't
carry such a keep). Narrow the keep to io.flutter.plugins.**; JNI-critical
embedding classes (FlutterJNI, …) stay via the embedding AAR's own consumer
ProGuard rules — verified the built APK still contains FlutterJNI and no
com.google.android.play.core.* at all. Also exclude the com.google.android.play
group at the dependency level (belt-and-suspenders) + -dontwarn.

Bumps to 0.1.15 (+17); fdroid recipe versionCodes 171/172/173.

apps/app_seeds/android/app/proguard-rules.pro

@@ -6,8 +6,14 @@
 # references and would strip/rename them. Keep them explicitly. Start
 # conservative; trim only after a release smoke test proves a class is unused.
 
-# --- Flutter engine & embedding (defensive; usually handled by the plugin) ---
--keep class io.flutter.** { *; }
+# --- Flutter engine & embedding ---
+# Do NOT blanket-keep io.flutter.** : that pins io.flutter.embedding.engine.
+# deferredcomponents.PlayStoreDeferredComponentManager, which references the
+# proprietary com.google.android.play.core.* (SplitInstall/SplitCompat) API and
+# makes F-Droid's scanner reject the APK. Tane doesn't use deferred components,
+# so let R8 shrink that unused manager away (removing the Play Core references).
+# JNI-critical embedding classes (FlutterJNI, etc.) are kept by the Flutter
+# embedding AAR's own bundled consumer ProGuard rules, so this stays safe.
 -keep class io.flutter.plugins.** { *; }
 -dontwarn io.flutter.embedding.**
 
@@ -38,3 +44,9 @@
 # --- Core library desugaring ---
 -dontwarn java.lang.invoke.**
 -dontwarn build.IgnoreJava8API
+
+# --- F-Droid: Google Play Core excluded (see build.gradle.kts) ---
+# The Flutter embedding references Play Core split-install classes for deferred
+# components, which Tane doesn't use; the com.google.android.play group is
+# excluded from the build, so tell R8 not to warn about the absent references.
+-dontwarn com.google.android.play.**