feat(workers): Implement geo-based task pools

Workers now follow the correct flow:
1. Check what pools have pending tasks
2. Claim a pool (e.g., Phoenix AZ)
3. Get Evomi proxy for that geo
4. Run preflight with geo proxy
5. Pull tasks from pool (up to 6 stores)
6. Execute tasks
7. Release pool when exhausted (6 stores visited)

Task pools group dispensaries by metro area (100mi radius):
- Phoenix AZ, Tucson AZ
- Los Angeles CA, San Francisco CA, San Diego CA, Sacramento CA
- Denver CO, Chicago IL, Boston MA, Detroit MI
- Las Vegas NV, Reno NV, Newark NJ, New York NY
- Oklahoma City OK, Tulsa OK, Portland OR, Seattle WA

Benefits:
- Workers know geo BEFORE getting proxy (no more "No geo assigned")
- IP diversity within metro area (Phoenix worker can use Tempe IP)
- Simpler worker logic - just match pool geo
- Pre-organized tasks, not grouped at claim time

New files:
- migrations/113_task_pools.sql - schema, seed data, functions
- src/services/task-pool.ts - TypeScript service

Env vars:
- USE_TASK_POOLS=true (new system)
- USE_IDENTITY_POOL=false (disabled)

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

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

k8s/scraper-worker.yaml

@@ -51,6 +51,13 @@ spec:
             # 3 browsers × ~400MB = ~1.3GB (safe for 2GB pod limit)
             - name: MAX_CONCURRENT_TASKS
               value: "3"
+            # Task Pool System (geo-based pools)
+            # Correct flow: check pools → claim pool → get proxy → preflight → pull tasks
+            - name: USE_TASK_POOLS
+              value: "true"
+            # Disable legacy identity pool
+            - name: USE_IDENTITY_POOL
+              value: "false"
           resources:
             requests:
               memory: "1Gi"