Implement RondevuAPI and RondevuSignaler classes

Added comprehensive API client and signaling implementation:

**RondevuAPI** - Single class for all Rondevu endpoints:
- Authentication: register()
- Offers: createOffers(), getOffer(), answerOffer(), getAnswer(), searchOffers()
- ICE Candidates: addIceCandidates(), getIceCandidates()
- Services: publishService(), getService(), searchServices()
- Usernames: checkUsername(), claimUsername()

**RondevuSignaler** - ICE candidate exchange:
- addIceCandidate() - Send local candidates to server
- addListener() - Poll for remote candidates (1 second intervals)
- Returns cleanup function (Binnable) to stop polling
- Handles offer expiration gracefully

**WebRTCRondevuConnection** - WebRTC connection wrapper:
- Handles offer/answer creation
- Manages ICE candidate exchange via Signaler
- Type-safe event bus for state changes and messages
- Queue and send message interfaces

**Utilities**:
- createBin() - Cleanup function collector
- Binnable type - Cleanup function signature

All classes use the shared RondevuAPI client for consistent
error handling and authentication.

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

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

src/types.ts

@@ -1,24 +1,34 @@
 /**
  * Core connection types
  */
+import {EventBus} from "./event-bus";
+import {Binnable} from "./bin";
 
-export interface ConnectionIdentity {
-    id: string;
-    hostUsername: string;
-}
-
-export interface ConnectionState {
-    state: 'connected' | 'disconnected' | 'connecting';
-    lastActive: number;
-}
+export type Message = string | ArrayBuffer;
 
 export interface QueueMessageOptions {
     expiresAt?: number;
 }
 
-export interface ConnectionInterface {
-    queueMessage(message: string | ArrayBuffer, options?: QueueMessageOptions): void;
-    sendMessage(message: string | ArrayBuffer): void;
+export interface ConnectionEvents {
+    'state-change': ConnectionInterface['state']
+    'message': Message;
 }
 
-export type Connection = ConnectionIdentity & ConnectionState & ConnectionInterface;
+export interface ConnectionInterface {
+    id: string;
+    host: string;
+    service: string;
+    state: 'connected' | 'disconnected' | 'connecting';
+    lastActive: number;
+    expiresAt?: number;
+    events: EventBus<ConnectionEvents>;
+
+    queueMessage(message: Message, options?: QueueMessageOptions): Promise<void>;
+    sendMessage(message: Message): Promise<boolean>;
+}
+
+export interface Signaler {
+    addIceCandidate(candidate: RTCIceCandidate): Promise<void> | void;
+    addListener(callback: (candidate: RTCIceCandidate) => void): Binnable;
+}