refactor: replace staging sync with REST bridge and add streaming backup
Phase 1: REST bridge
- New ResticRestBridge (NanoHTTPD) implementing restic REST protocol
- New RestBridgeRunner lifecycle manager (withBridge pattern)
- ResticEnvResolver: buildLocalEnv/buildBridgeEnv split
- ResticWrapper: syncManager → bridgeRunner, propagate cacheDir
- 5 sub-modules (Backup/Restore/SnapshotOps/Maintenance/RepoInit):
unified local/bridge branching
- Delete RemoteSyncManager.kt (231 lines removed)
- Clean RemoteTransport companion (only create() remains)
- Remove getTempRepoDir, cleanup(), onSyncProgress/ByteSyncProgress
Phase 2: Streaming backup
- New StreamingBackup with FIFO orchestration
- ResticBackup.backupStdin() with --stdin mode
- ResticCommandRunner.runResticWithStdin() (API 24 compat)
- BackupFragment: space detection + auto-switch to streaming
Code quality fixes:
- OOM protection: stream blob bodies to temp files
- API compat: manual stdin piping (no redirectInput API 26)
- Build: 0 errors, 0 warnings, lint 0 errors, all 53 tests pass
7e98e0f78e