feat: add kickstart prompt and auto-compact context options

Kickstart Prompt:
- Remove Idle Timeout setting from respawn UI (uses 10s default)
- Add Kickstart Prompt field sent when /init doesn't trigger work
- New states: monitoring_init, sending_kickstart, waiting_kickstart
- Monitors 3s after /init to detect if Claude started working

Auto-Compact Context:
- Add auto-compact at 110k tokens (sends /compact with optional prompt)
- Preserves summarized context unlike /clear which wipes everything
- Optional focus prompt to guide what compact should preserve
- Blocks auto-clear while compacting to prevent conflicts

Also updates auto-clear default threshold from 100k to 140k tokens.

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

src/web/server.ts

@@ -515,6 +515,29 @@ export class WebServer extends EventEmitter {
       };
     });
 
+    // Set auto-compact on a session
+    this.app.post('/api/sessions/:id/auto-compact', async (req) => {
+      const { id } = req.params as { id: string };
+      const body = req.body as { enabled: boolean; threshold?: number; prompt?: string };
+      const session = this.sessions.get(id);
+
+      if (!session) {
+        return { error: 'Session not found' };
+      }
+
+      session.setAutoCompact(body.enabled, body.threshold, body.prompt);
+      this.broadcast('session:updated', session.toDetailedState());
+
+      return {
+        success: true,
+        autoCompact: {
+          enabled: session.autoCompactEnabled,
+          threshold: session.autoCompactThreshold,
+          prompt: session.autoCompactPrompt,
+        },
+      };
+    });
+
     // Quick run (create session, run prompt, return result, then cleanup)
     this.app.post('/api/run', async (req) => {
       // Prevent unbounded session creation
@@ -912,6 +935,11 @@ export class WebServer extends EventEmitter {
       this.broadcast('session:autoClear', { sessionId: session.id, ...data });
       this.broadcast('session:updated', session.toDetailedState());
     });
+
+    session.on('autoCompact', (data: { tokens: number; threshold: number; prompt?: string }) => {
+      this.broadcast('session:autoCompact', { sessionId: session.id, ...data });
+      this.broadcast('session:updated', session.toDetailedState());
+    });
   }
 
   private setupRespawnListeners(sessionId: string, controller: RespawnController): void {