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>

pwa/README.md

@@ -1,32 +1,18 @@
-# React + TypeScript + Vite
+# flit — PWA
 
-This template provides a minimal setup to get React working in Vite with HMR and some Oxlint rules.
+React/TypeScript/Vite frontend. See the [root README](../README.md) for the full project overview.
 
-Currently, two official plugins are available:
+## Development
 
-- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Oxc](https://oxc.rs)
-- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/)
-
-## React Compiler
-
-The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see [this documentation](https://react.dev/learn/react-compiler/installation).
-
-## Expanding the Oxlint configuration
-
-If you are developing a production application, we recommend enabling type-aware lint rules by installing `oxlint-tsgolint` and editing `.oxlintrc.json`:
-
-```json
-{
-  "$schema": "./node_modules/oxlint/configuration_schema.json",
-  "plugins": ["react", "typescript", "oxc"],
-  "options": {
-    "typeAware": true
-  },
-  "rules": {
-    "react/rules-of-hooks": "error",
-    "react/only-export-components": ["warn", { "allowConstantExport": true }]
-  }
-}
+```bash
+npm install
+npm run dev      # dev server at localhost:5173
+npm run build    # output to dist/
+npm run lint
 ```
 
-See the [Oxlint rules documentation](https://oxc.rs/docs/guide/usage/linter/rules) for the full list of rules and categories.
+`public/config.js` sets the anchor and TURN URLs at runtime and is excluded from production deploys (so the host copy isn't overwritten). The repo's default points at the live anchor — fine for local dev.
+
+## Deploy
+
+See `../deploy-pwa.sh` and `../serve-pwa.sh` at the repo root.