feat: implement on-demand cleanup triggered after analysis completion

- Replace time-based cleanup with on-demand cleanup in development mode
- Cleanup is triggered immediately after AI analysis completes
- Added runPostAnalysisCleanup() method to aggressive-cleanup service
- Cleanup triggers added to both single and batch analysis endpoints
- More efficient: cleanup happens only when needed, not on timer
- Prevents zombie processes without interfering with active analysis
- Production mode still uses periodic cleanup as backup (10 min intervals)
- Gentle cleanup in development: SIGTERM first, then SIGKILL if needed

lib/ai-analysis.ts

@@ -718,6 +718,19 @@ Analyze all provided screenshots comprehensively and return only the JSON respon
         setTimeout(() => progressTracker.deleteSession(sessionId), 1000)
       }
       
+      // Trigger post-analysis cleanup in development mode
+      if (process.env.NODE_ENV === 'development') {
+        try {
+          // Dynamic import to avoid circular dependencies
+          const aggressiveCleanupModule = await import('./aggressive-cleanup')
+          const aggressiveCleanup = aggressiveCleanupModule.default
+          // Run cleanup in background, don't block the response
+          aggressiveCleanup.runPostAnalysisCleanup().catch(console.error)
+        } catch (cleanupError) {
+          console.error('Error triggering post-analysis cleanup:', cleanupError)
+        }
+      }
+      
       return {
         screenshots,
         analysis