feat: add repository_dispatch event support

- Add new progress MCP server for reporting task status via API
- Support repository_dispatch events with task description and progress endpoint
- Introduce isDispatch flag to unify dispatch event handling
- Make GitHub data optional for dispatch events without issues/PRs
- Update prompt generation with dispatch-specific instructions

Enables triggering Claude via repository_dispatch with:
{
  "event_type": "claude_task",
  "client_payload": {
    "description": "Task description",
    "progress_endpoint": "https://api.example.com/progress"
  }
}

src/types/stream-config.ts

@@ -0,0 +1,19 @@
+/**
+ * Configuration for streaming and progress tracking
+ */
+export type StreamConfig = {
+  /** Endpoint for streaming Claude execution progress */
+  progress_endpoint?: string;
+
+  /** Endpoint for system-level progress reporting (workflow lifecycle events) */
+  system_progress_endpoint?: string;
+
+  /** Resume endpoint for teleport functionality */
+  resume_endpoint?: string;
+
+  /** Session ID for tracking */
+  session_id?: string;
+
+  /** Headers to include with streaming requests (includes Authorization) */
+  headers?: Record<string, string>;
+};