Strip client to minimal skeleton with ConnectionManager

Removed all complex implementations and kept only the essentials:
- Removed durable/ directory (DurableConnection, DurableChannel, etc.)
- Removed peer/ directory (entire state machine)
- Removed service-pool.ts, offer-pool.ts, rondevu.ts
- Removed auth.ts, offers.ts, usernames.ts, event-emitter.ts
- Added empty ConnectionManager class as starting point

The client now contains just:
- src/connection-manager.ts - Empty class skeleton
- src/index.ts - Simple export

This provides a clean slate to rebuild the client with a simpler
architecture focused on core WebRTC connection management.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -27,6 +27,7 @@
     "README.md"
   ],
   "dependencies": {
-    "@noble/ed25519": "^3.0.0"
+    "@noble/ed25519": "^3.0.0",
+    "@xtr-dev/rondevu-client": "^0.9.2"
   }
 }