Add durable WebRTC connections with auto-reconnect and message buffering (v0.18.8)

- Add connection state machine with proper lifecycle management
- Implement automatic reconnection with exponential backoff
- Add message buffering during disconnections
- Create RondevuConnection base class with state tracking
- Create OffererConnection and AnswererConnection classes
- Fix ICE polling lifecycle (now stops when connected)
- Add fillOffers() semaphore to prevent exceeding maxOffers
- Implement answer fingerprinting to prevent duplicate processing
- Add dual ICE state monitoring (iceConnectionState + connectionState)
- Fix data channel handler timing issues
- Add comprehensive event system (20+ events)
- Add connection timeouts and proper cleanup

Breaking changes:
- connectToService() now returns AnswererConnection instead of ConnectionContext
- connection:opened event signature changed: (offerId, dc) → (offerId, connection)
- Direct DataChannel access replaced with connection wrapper API

See MIGRATION.md for upgrade guide.

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

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

src/connection-events.ts

@@ -0,0 +1,102 @@
+/**
+ * TypeScript event type definitions for RondevuConnection
+ */
+
+export enum ConnectionState {
+    INITIALIZING = 'initializing',    // Creating peer connection
+    GATHERING = 'gathering',          // ICE gathering in progress
+    SIGNALING = 'signaling',          // Exchanging offer/answer
+    CHECKING = 'checking',            // ICE connectivity checks
+    CONNECTING = 'connecting',        // ICE connection attempts
+    CONNECTED = 'connected',          // Data channel open, working
+    DISCONNECTED = 'disconnected',    // Temporarily disconnected
+    RECONNECTING = 'reconnecting',    // Attempting reconnection
+    FAILED = 'failed',                // Connection failed
+    CLOSED = 'closed',                // Connection closed permanently
+}
+
+export interface BufferedMessage {
+    id: string
+    data: string | ArrayBuffer | Blob
+    timestamp: number
+    attempts: number
+}
+
+export interface ReconnectInfo {
+    attempt: number
+    delay: number
+    maxAttempts: number
+}
+
+export interface StateChangeInfo {
+    oldState: ConnectionState
+    newState: ConnectionState
+    reason?: string
+}
+
+/**
+ * Event map for RondevuConnection
+ * Maps event names to their payload types
+ */
+export interface ConnectionEventMap {
+    // Lifecycle events
+    'state:changed': [StateChangeInfo]
+    'connecting': []
+    'connected': []
+    'disconnected': [reason?: string]
+    'failed': [error: Error]
+    'closed': [reason?: string]
+
+    // Reconnection events
+    'reconnect:scheduled': [ReconnectInfo]
+    'reconnect:attempting': [attempt: number]
+    'reconnect:success': []
+    'reconnect:failed': [error: Error]
+    'reconnect:exhausted': [attempts: number]
+
+    // Message events
+    'message': [data: string | ArrayBuffer | Blob]
+    'message:sent': [data: string | ArrayBuffer | Blob, buffered: boolean]
+    'message:buffered': [data: string | ArrayBuffer | Blob]
+    'message:replayed': [message: BufferedMessage]
+    'message:buffer:overflow': [discardedMessage: BufferedMessage]
+    'message:buffer:expired': [message: BufferedMessage]
+
+    // ICE events
+    'ice:candidate:local': [candidate: RTCIceCandidate | null]
+    'ice:candidate:remote': [candidate: RTCIceCandidate | null]
+    'ice:connection:state': [state: RTCIceConnectionState]
+    'ice:gathering:state': [state: RTCIceGatheringState]
+    'ice:polling:started': []
+    'ice:polling:stopped': []
+
+    // Answer processing events (offerer only)
+    'answer:processed': [offerId: string, answererId: string]
+    'answer:duplicate': [offerId: string]
+
+    // Data channel events
+    'datachannel:open': []
+    'datachannel:close': []
+    'datachannel:error': [error: Event]
+
+    // Cleanup events
+    'cleanup:started': []
+    'cleanup:complete': []
+
+    // Connection events (mirrors RTCPeerConnection.connectionState)
+    'connection:state': [state: RTCPeerConnectionState]
+
+    // Timeout events
+    'connection:timeout': []
+    'ice:gathering:timeout': []
+}
+
+/**
+ * Helper type to extract event names from the event map
+ */
+export type ConnectionEventName = keyof ConnectionEventMap
+
+/**
+ * Helper type to extract event arguments for a specific event
+ */
+export type ConnectionEventArgs<T extends ConnectionEventName> = ConnectionEventMap[T]