feat(tasks): Add unified task-based worker architecture

Replace fragmented job systems (job_schedules, dispensary_crawl_jobs, SyncOrchestrator)
with a single unified task queue:

- Add worker_tasks table with atomic task claiming via SELECT FOR UPDATE SKIP LOCKED
- Add TaskService for CRUD, claiming, and capacity metrics
- Add TaskWorker with role-based handlers (resync, discovery, analytics)
- Add /api/tasks endpoints for management and migration from legacy systems
- Add TasksDashboard UI and integrate task counts into main dashboard
- Add comprehensive documentation

Task roles: store_discovery, entry_point_discovery, product_discovery, product_resync, analytics_refresh

Run workers with: WORKER_ROLE=product_resync npx tsx src/tasks/task-worker.ts

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

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

backend/src/tasks/handlers/analytics-refresh.ts

@@ -0,0 +1,92 @@
+/**
+ * Analytics Refresh Handler
+ *
+ * Refreshes materialized views and pre-computed analytics tables.
+ * Should run daily or on-demand after major data changes.
+ */
+
+import { TaskContext, TaskResult } from '../task-worker';
+
+export async function handleAnalyticsRefresh(ctx: TaskContext): Promise<TaskResult> {
+  const { pool } = ctx;
+
+  console.log(`[AnalyticsRefresh] Starting analytics refresh...`);
+
+  const refreshed: string[] = [];
+  const failed: string[] = [];
+
+  // List of materialized views to refresh
+  const materializedViews = [
+    'mv_state_metrics',
+    'mv_brand_metrics',
+    'mv_category_metrics',
+    'v_brand_summary',
+    'v_dashboard_stats',
+  ];
+
+  for (const viewName of materializedViews) {
+    try {
+      // Heartbeat before each refresh
+      await ctx.heartbeat();
+
+      // Check if view exists
+      const existsResult = await pool.query(`
+        SELECT EXISTS (
+          SELECT 1 FROM pg_matviews WHERE matviewname = $1
+          UNION
+          SELECT 1 FROM pg_views WHERE viewname = $1
+        ) as exists
+      `, [viewName]);
+
+      if (!existsResult.rows[0].exists) {
+        console.log(`[AnalyticsRefresh] View ${viewName} does not exist, skipping`);
+        continue;
+      }
+
+      // Try to refresh (only works for materialized views)
+      try {
+        await pool.query(`REFRESH MATERIALIZED VIEW CONCURRENTLY ${viewName}`);
+        refreshed.push(viewName);
+        console.log(`[AnalyticsRefresh] Refreshed ${viewName}`);
+      } catch (refreshError: any) {
+        // Try non-concurrent refresh
+        try {
+          await pool.query(`REFRESH MATERIALIZED VIEW ${viewName}`);
+          refreshed.push(viewName);
+          console.log(`[AnalyticsRefresh] Refreshed ${viewName} (non-concurrent)`);
+        } catch (nonConcurrentError: any) {
+          // Not a materialized view or other error
+          console.log(`[AnalyticsRefresh] ${viewName} is not a materialized view or refresh failed`);
+        }
+      }
+    } catch (error: any) {
+      console.error(`[AnalyticsRefresh] Error refreshing ${viewName}:`, error.message);
+      failed.push(viewName);
+    }
+  }
+
+  // Run analytics capture functions if they exist
+  const captureFunctions = [
+    'capture_brand_snapshots',
+    'capture_category_snapshots',
+  ];
+
+  for (const funcName of captureFunctions) {
+    try {
+      await pool.query(`SELECT ${funcName}()`);
+      console.log(`[AnalyticsRefresh] Executed ${funcName}()`);
+    } catch (error: any) {
+      // Function might not exist
+      console.log(`[AnalyticsRefresh] ${funcName}() not available`);
+    }
+  }
+
+  console.log(`[AnalyticsRefresh] Complete: ${refreshed.length} refreshed, ${failed.length} failed`);
+
+  return {
+    success: failed.length === 0,
+    refreshed,
+    failed,
+    error: failed.length > 0 ? `Failed to refresh: ${failed.join(', ')}` : undefined,
+  };
+}