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/src/main/kotlin/com/syncflow/data/db/DbConverters.kt

@@ -0,0 +1,9 @@
+package com.syncflow.data.db
+
+import androidx.room.TypeConverter
+import java.time.Instant
+
+class DbConverters {
+    @TypeConverter fun fromInstant(v: Instant?): Long? = v?.epochSecond
+    @TypeConverter fun toInstant(v: Long?): Instant? = v?.let { Instant.ofEpochSecond(it) }
+}