Gallery Sync

Architecture

Android App  <──── wss:// (LAN, pinned self-signed TLS) ────>  Desktop App
    │                                                                │
  Gallery UI (Compose)                                    Gallery UI (React)
    │                                                                │
  SyncClient (network module)                          sync server (axum + rustls)
    │                                                                │
  media_index.db (SHA-256 hash index, phone-local)          catalog.db (SQLite, PC-local)
                                                        + on-disk thumbnail/original cache

• Pairing: PC renders a QR (LAN IP, port, one-off session token, TLS public-key fingerprint); phone scans and dials wss://.
• Catalog sync: phone hashes its media (SHA-256, opt-in/manual — never automatic, to protect battery), sends a paged, delta-aware catalog; the PC diffs against what it already has.
• Thumbnails: PC auto-requests previews for anything unsent right after a successful pairing/reconnect; phone streams them continuously.
• Originals (backup): full-resolution files move only on explicit request — either the phone pushing one via its own cloud-icon action, or the PC pushing a backup_request for a multi-selected batch through a live-connection registry that reaches directly into the phone's open socket.
• Everything phone-sourced is additive, never destructive: a file deleted on the phone is not deleted from the PC's backup — this is a backup tool, not a mirror.

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