Add ServiceHost, ServiceClient, and RondevuService for high-level service management

- Add RondevuService: High-level API for username claiming and service publishing with Ed25519 signatures
- Add ServiceHost: Manages offer pool for hosting services with auto-replacement
- Add ServiceClient: Connects to hosted services with automatic reconnection
- Add NoOpSignaler: Placeholder signaler for connection setup
- Integrate Ed25519 signature functionality from @noble/ed25519
- Add ESLint and Prettier configuration with 4-space indentation
- Add demo with local signaling test
- Version bump to 0.10.0

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

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

.prettierrc.json

@@ -0,0 +1,9 @@
+{
+    "semi": false,
+    "singleQuote": true,
+    "tabWidth": 4,
+    "useTabs": false,
+    "trailingComma": "es5",
+    "printWidth": 100,
+    "arrowParens": "avoid"
+}