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/types.ts

@@ -74,6 +74,8 @@ export interface RespawnConfig {
   sendClear: boolean;
   /** Whether to send /init after /clear */
   sendInit: boolean;
+  /** Optional prompt to send if /init doesn't trigger work */
+  kickstartPrompt?: string;
 }
 
 export interface AppConfig {