Add PWA, CLI daemon, deploy tooling, and full documentation

PWA (pwa/):
- Ephemeral QR pairing and trusted device direct reconnect (no QR re-scan)
- Known devices tab as default; pairRoomName() derives deterministic room
- In-app QR scanner via native BarcodeDetector API
- Multi-file send/receive with offer queue and Accept all
- Auto-download on receipt, real-time send/receive progress bars
- Trusted peer nicknames, rename, forget
- Terminal aesthetic: #080808 bg, #00e87a accent, JetBrains Mono
- manifest.json corrected (SVG icon, theme_color, share_target)
- Apple PWA meta tags for home screen install

CLI (cli/):
- flit send / flit recv: ephemeral one-shot transfer with terminal QR
- flit daemon: persistent receiver for trusted peers from ~/.flit/daemon.toml
  - TOML config: signal_url, turn_url, download_dir, [[peers]]
  - One goroutine per peer, exponential backoff reconnect (2s→30s cap)
  - transport.PairRoomName() and Session.OnDisconnected added
- Anchor/TURN config via FLIT_SIGNAL_URL / FLIT_TURN_URL env vars (no hardcoded URLs)

Deploy:
- build-pwa.sh, deploy-pwa.sh / serve-pwa.sh templates in README (gitignored)
- .gitea/workflows/build.yml: PWA build on v* tag, Gitea release artifact
- pwa/public/config.js gitignored; config.js.example committed
- .env.example for CLI env vars

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

cli/daemon.toml.example

@@ -0,0 +1,26 @@
+# flit daemon config — copy to ~/.flit/daemon.toml and fill in.
+#
+# Run with: flit daemon
+# Files land in download_dir as peers send them.
+
+# Required — WebSocket URL of your waste-go anchor
+signal_url = "wss://your-anchor.example.com/ws"
+
+# Optional — TURN relay for cross-network transfers
+turn_url    = "turn:your-anchor.example.com:3478"
+turn_secret = ""   # coturn use-auth-secret; leave empty to use STUN only
+
+# Directory where received files are saved (~ is expanded)
+download_dir = "~/flit-inbox"
+
+# Trusted peers — add one [[peers]] block per device.
+# Get a peer's id by pairing once via `flit send` / PWA and reading
+# the "peer connected" log line, or from the PWA's Known devices list.
+
+[[peers]]
+id    = "aabbccddeeff..."   # hex Ed25519 pubkey
+label = "phone"
+
+[[peers]]
+id    = "112233445566..."
+label = "laptop"