feat: add smart respawn integration and priority todos (Phase 2)

Smart Respawn Integration (2.5):
- Check circuit breaker OPEN state before respawn (blocks cycle)
- Check RALPH_STATUS EXIT_SIGNAL=true to stop respawn
- Check STATUS=BLOCKED to pause respawn for human intervention
- Use RECOMMENDATION from RALPH_STATUS in update prompt
- Emit respawn:blocked SSE event with reason and details
- Show notification when respawn is blocked
- Visual blocked state with pulsing red indicator

Priority-based Todos (part of 2.3):
- Add RalphTodoPriority type (P0/P1/P2/null)
- Parse priority from todo content (P0:, Critical:, High Priority, etc.)
- Add priority field to RalphTodoItem interface
- Update frontend to display priority badges with colors
- Sort todos by priority (P0 > P1 > P2) then by status
- Add CSS for priority badges and highlighted cards

Bump version to 0.1391

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

src/web/server.ts

@@ -2532,6 +2532,13 @@ export class WebServer extends EventEmitter {
       this.broadcast('respawn:cycleCompleted', { sessionId, cycleNumber });
     });
 
+    controller.on('respawnBlocked', (data: { reason: string; details: string }) => {
+      this.broadcast('respawn:blocked', { sessionId, reason: data.reason, details: data.details });
+      // Track in run summary (lazy lookup)
+      const tracker = getTracker();
+      if (tracker) tracker.recordWarning(`Respawn blocked: ${data.reason}`, data.details);
+    });
+
     controller.on('stepSent', (step: string, input: string) => {
       this.broadcast('respawn:stepSent', { sessionId, step, input });
     });