Add heartbeat integration, planning phase, and auto-repair

- Add HeartbeatConfig for proactive periodic execution with channel notifications
- Add use_planning option to Worker for ActionPlan generation before tool execution
- Implement tool failure tracking in database (V3 migration)
- Add auto-repair via Builder for broken WASM tools in self_repair.rs
- Record tool failures in Worker for self-repair tracking
- Update .env.example with new configuration options

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/main.rs

@@ -192,6 +192,7 @@ async fn main() -> anyhow::Result<()> {
         tools,
         channels,
         workspace,
+        Some(config.heartbeat.clone()),
     );
 
     tracing::info!("Agent initialized, starting main loop...");