fix(workers): Fix false memory backoff and add backing-off color coding

- Fix memory calculation to use max-old-space-size (1500MB) instead of
  V8's dynamic heapTotal. This prevents false 95%+ readings when idle.
- Add yellow color for backing-off workers in pod visualization
- Update legend and tooltips with backing-off status
- Remove pool toggle from TasksDashboard (moved to Workers page)

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

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

k8s/scraper-worker.yaml

@@ -40,12 +40,16 @@ spec:
               valueFrom:
                 fieldRef:
                   fieldPath: metadata.name
+            - name: API_BASE_URL
+              value: "http://scraper"
+            - name: NODE_OPTIONS
+              value: "--max-old-space-size=1500"
           resources:
             requests:
-              memory: "256Mi"
+              memory: "1Gi"
               cpu: "100m"
             limits:
-              memory: "512Mi"
+              memory: "2Gi"
               cpu: "500m"
           livenessProbe:
             exec: