Initial commit — SyncFlow Android file sync app

Supports WebDAV, SFTP, SFTPGo, Nextcloud, ownCloud, Google Drive,
Dropbox, and OneDrive. Credentials encrypted with Android Keystore.
Biometric app-lock, conflict resolution, and auto-sync via WorkManager.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/proguard-rules.pro

@@ -0,0 +1,8 @@
+-keep class com.syncflow.data.db.entities.** { *; }
+-keep class com.syncflow.domain.model.** { *; }
+-keep class com.google.api.** { *; }
+-keep class com.dropbox.** { *; }
+-keep class com.microsoft.graph.** { *; }
+-dontwarn org.bouncycastle.**
+-dontwarn org.conscrypt.**
+-dontwarn org.openjsse.**