Initial commit: BountyBoard Android client

Native Kotlin + Jetpack Compose (Material 3) client for the BountyBoard
platform. Cookie-session + CSRF auth with a configurable base URL, the full
role-based feature set (admin / consultant / developer), local + OIDC SSO
sign-in, and background push notifications (WorkManager poll) for alerts and
messages. Bundles the app's editorial "ledger" design system and the original
Fraunces / Schibsted Grotesk / Spline Sans Mono typefaces.

Includes a prebuilt debug APK (BountyBoard-debug.apk) for side-loading.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/proguard-rules.pro

@@ -0,0 +1,8 @@
+# Retrofit / Gson models are accessed reflectively.
+-keep class com.anypreta.bountyboard.data.model.** { *; }
+-keepattributes Signature, *Annotation*
+-keepclassmembers,allowobfuscation class * {
+  @com.google.gson.annotations.SerializedName <fields>;
+}
+-dontwarn okhttp3.**
+-dontwarn retrofit2.**