Initial commit: ContactSync Android app

- SyncAdapter with account type com.bitrix24.contacts.sync
- Two-phase sync: download to Room DB, then import to phone contacts
- FCM push for instant contact addition
- WorkManager: periodic sync (30min) + heartbeat (1h)
- QR code activation (JSON format)
- Event log UI with LiveData
- Auto-update mechanism via version.php
- Duplicate contacts cleanup
- CALLER_IS_SYNCADAPTER optimization for bulk inserts

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

app/proguard-rules.pro

@@ -0,0 +1,10 @@
+# Retrofit
+-keepattributes Signature
+-keepattributes *Annotation*
+-keep class com.bitrix24.contactsync.data.api.** { *; }
+-dontwarn okhttp3.**
+-dontwarn retrofit2.**
+
+# Room
+-keep class * extends androidx.room.RoomDatabase
+-keep @androidx.room.Entity class *