feat: phase 10 — reconnection, encoding 10, disconnect button

Frontend reconnection:
- WebSocket auto-reconnects with exponential backoff (1s → 30s)
- Re-authenticates with OmniView to get fresh APPLET_ID on reconnect
- Credentials stored in sessionStorage for automatic re-login
- Status bar shows connection state and reconnect countdown
- Disconnect button returns to login screen

Encoding 10 (Raw with tile interleave):
- codec/raw_tile.rs: decodes encoding 10 per ByteColorRFBRenderer.for()
- Flag byte bit 0 selects plain raw vs 16x16 tile-interleaved data
- Deinterleave handles edge tiles smaller than 16x16
- Wired into session dispatch
- 2 unit tests

39 tests passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/ericrfb/src/codec/mod.rs

@@ -1,2 +1,3 @@
 pub mod hextile;
+pub mod raw_tile;
 pub mod tight;