feat: show live print progress in the browser tab title

Optional and off by default, toggled under Settings -> Appearance. When enabled, the browser tab shows the soonest-finishing print's percentage plus a green progress-ring favicon, updated live over the existing WebSocket. The preference is stored per-browser in localStorage.

Adds the usePrintProgressTitle hook (with tests), a ThemeContext preference, the Settings toggle, i18n strings for all locales, and a README entry.

README.md

@@ -156,6 +156,7 @@ Optional but recommended — drop the [`slicer-api/` Compose stack](slicer-api/R
 
 ### 📊 Monitoring & Control
 - Real-time printer status via WebSocket
+- **Print progress in the browser tab** — optional (off by default, toggle under Settings → Appearance): shows the soonest-finishing print's percentage in the tab title and a progress-ring favicon in your theme accent colour
 - Live camera streaming (MJPEG) & snapshots with multi-viewer support — most Bambu printers only allow one upstream connection, so Bambuddy fans out a single shared stream to all browser tabs / cards / overlays
 - **Cam Wall view** — Toggle the Printers page from cards into a responsive grid of camera tiles for at-a-glance monitoring across the whole farm. On-screen tiles stream live up to a configurable cap (default 4) so RPi installs stay sustainable; the rest fall back to periodic snapshot polling, and off-screen tiles pause entirely. Per-user settings (live cap, snapshot interval); click any tile to open the floating viewer or the dedicated camera window depending on your existing camera-view preference
 - **Long-lived camera tokens** for Home Assistant / Frigate / kiosks — mint a token from Settings → API Keys, paste it once, capped at 365 days, revocable at any time (no infinite tokens — leaked permanent tokens are unsafe by design)