feat: Performance optimizations and preflight improvements

- Add missing /api/analytics/national/summary endpoint
- Optimize dashboard activity queries (subquery vs JOIN+GROUP BY)
- Add PreflightSummary component to Workers page with gold qualified badge
- Add preflight retry logic - workers retry every 30s until qualified
- Run stale task cleanup on ALL workers (not just worker-0)
- Add preflight fields to worker-registry API (ip, fingerprint, is_qualified)

Database indexes added:
- idx_store_products_created_at (for recent products)
- idx_dispensaries_last_crawl_at (for recent scrapes)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/src/tasks/task-worker.ts

@@ -273,6 +273,16 @@ export class TaskWorker {
   private preflightsCompleted: boolean = false;
   private initializingPromise: Promise<void> | null = null;
 
+  // ==========================================================================
+  // PREFLIGHT RETRY SETTINGS
+  // ==========================================================================
+  // If preflight fails, worker retries every PREFLIGHT_RETRY_INTERVAL_MS
+  // Worker is BLOCKED from claiming ANY tasks until preflight passes.
+  // This ensures unqualified workers never touch the task pool.
+  // ==========================================================================
+  private static readonly PREFLIGHT_RETRY_INTERVAL_MS = 30000; // 30 seconds
+  private isRetryingPreflight: boolean = false;
+
   // ==========================================================================
   // STEP TRACKING FOR DASHBOARD VISIBILITY
   // ==========================================================================
@@ -617,6 +627,75 @@ export class TaskWorker {
     }
   }
 
+  /**
+   * Retry preflight until it passes.
+   * Worker is BLOCKED from claiming ANY tasks until HTTP preflight passes.
+   * This ensures unqualified workers never touch the task pool.
+   *
+   * All current tasks require 'http' method, so HTTP preflight is mandatory.
+   */
+  private async retryPreflightUntilPass(): Promise<void> {
+    if (this.preflightHttpPassed) {
+      return; // Already passed
+    }
+
+    if (this.isRetryingPreflight) {
+      return; // Already retrying
+    }
+
+    this.isRetryingPreflight = true;
+    let retryCount = 0;
+
+    console.log(`[TaskWorker] ${this.friendlyName} HTTP preflight FAILED - entering retry loop (every ${TaskWorker.PREFLIGHT_RETRY_INTERVAL_MS / 1000}s)`);
+    console.log(`[TaskWorker] ${this.friendlyName} BLOCKED from task pool until preflight passes`);
+
+    while (!this.preflightHttpPassed && this.isRunning) {
+      retryCount++;
+
+      // Wait before retry
+      await this.sleep(TaskWorker.PREFLIGHT_RETRY_INTERVAL_MS);
+
+      if (!this.isRunning) {
+        break; // Worker stopping
+      }
+
+      console.log(`[TaskWorker] ${this.friendlyName} preflight retry #${retryCount}...`);
+
+      // Reload proxies before retry (might have new ones)
+      try {
+        await this.crawlRotator.initialize();
+        const stats = this.crawlRotator.proxy.getStats();
+        console.log(`[TaskWorker] Proxies available: ${stats.activeProxies}`);
+      } catch (err: any) {
+        console.warn(`[TaskWorker] Proxy reload failed: ${err.message}`);
+      }
+
+      // Re-run HTTP preflight
+      try {
+        const httpResult = await runPuppeteerPreflightWithRetry(this.crawlRotator, 1);
+        this.preflightHttpResult = httpResult;
+        this.preflightHttpPassed = httpResult.passed;
+
+        if (httpResult.passed) {
+          console.log(`[TaskWorker] ${this.friendlyName} HTTP preflight PASSED on retry #${retryCount}!`);
+          console.log(`[TaskWorker] ${this.friendlyName} IP: ${httpResult.proxyIp}, Products: ${httpResult.productsReturned}`);
+          console.log(`[TaskWorker] ${this.friendlyName} now QUALIFIED to claim tasks`);
+
+          // Report updated status
+          await this.reportPreflightStatus();
+          break;
+        } else {
+          console.log(`[TaskWorker] ${this.friendlyName} HTTP preflight still FAILED: ${httpResult.error}`);
+          console.log(`[TaskWorker] ${this.friendlyName} will retry in ${TaskWorker.PREFLIGHT_RETRY_INTERVAL_MS / 1000}s...`);
+        }
+      } catch (err: any) {
+        console.error(`[TaskWorker] ${this.friendlyName} preflight retry error: ${err.message}`);
+      }
+    }
+
+    this.isRetryingPreflight = false;
+  }
+
   /**
    * Lazy initialization of stealth systems.
    * Called BEFORE claiming first task (not at worker startup).
@@ -855,15 +934,14 @@ export class TaskWorker {
     // Start registry heartbeat immediately
     this.startRegistryHeartbeat();
 
-    // Cleanup stale tasks on startup and periodically (only worker-0 does this to avoid races)
-    // This handles tasks left in 'claimed'/'running' status when workers restart or crash
-    if (this.workerId.endsWith('-0') || this.workerId === 'scraper-worker-0') {
-      // Run immediately on startup
-      await this.runStaleTaskCleanup();
+    // Cleanup stale tasks on startup and periodically
+    // ALL workers run cleanup to ensure stale tasks are recovered even if some workers crash
+    // The cleanup query uses SELECT FOR UPDATE SKIP LOCKED to avoid races
+    // Run immediately on startup
+    await this.runStaleTaskCleanup();
 
-      // Start periodic cleanup every 10 minutes
-      this.startPeriodicStaleCleanup();
-    }
+    // Start periodic cleanup every 10 minutes
+    this.startPeriodicStaleCleanup();
 
     const roleMsg = this.role ? `for role: ${this.role}` : '(role-agnostic - any task)';
     console.log(`[TaskWorker] ${this.friendlyName} starting ${roleMsg} (stealth=lazy, max ${this.maxConcurrentTasks} concurrent tasks)`);
@@ -940,6 +1018,18 @@ export class TaskWorker {
         }
       }
 
+      // =================================================================
+      // PREFLIGHT GATE - BLOCK unqualified workers from task pool
+      // All tasks require HTTP method, so HTTP preflight MUST pass.
+      // If preflight failed, worker retries every 30 seconds.
+      // Worker CANNOT claim ANY tasks until preflight passes.
+      // =================================================================
+      if (!this.preflightHttpPassed) {
+        console.log(`[TaskWorker] ${this.friendlyName} BLOCKED - HTTP preflight not passed, cannot claim tasks`);
+        await this.retryPreflightUntilPass();
+        return; // Return to main loop, will re-check on next iteration
+      }
+
       // Pass preflight capabilities to only claim compatible tasks
       const task = await taskService.claimTask(
         this.role,