backend: GDPR export + retention cleanups + worker metrics (BE-1/2/3)

BE-3 observability: expose the worker's Prometheus metrics on :6060/metrics
(apns/fcm/asynq histograms + a new cache_ops_total counter were recorded all
along but never scraped — which is why those dashboard panels read empty); add
the worker containerPort, the vmagent worker scrape job, and two additive
NetworkPolicies. Instrument cache Get/Set hit/miss.

BE-2 retention: three periodic Asynq cleanup crons mirroring the reminder-log
cleanup — notifications (90d), webhook dedup log (180d), audit_log (365d).

BE-1 GDPR data export: POST /api/auth/export/ enqueues a low-priority Asynq job
that gathers all of the user's data (owned residences + their tasks/contractors/
documents/share-codes, plus profile/notifications/prefs/push-tokens/subscription/
audit log), zips one JSON file per category, and emails it as an attachment.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

deploy-k3s/manifests/observability/vmagent.yaml

@@ -78,18 +78,25 @@ data:
           - target_label: service
             replacement: node-exporter
 
-      # honeyDue worker — also exposes /metrics if/when we add it.
-      # Keep this stanza commented until the worker has a /metrics endpoint;
-      # uncommented form drops scrapes silently.
-      # - job_name: worker
-      #   kubernetes_sd_configs:
-      #     - role: pod
-      #       namespaces:
-      #         names: [honeydue]
-      #   relabel_configs:
-      #     - source_labels: [__meta_kubernetes_pod_label_app_kubernetes_io_name]
-      #       action: keep
-      #       regex: worker
+      # honeyDue worker — exposes /metrics on :6060 (apns/fcm/asynq/cache series).
+      - job_name: worker
+        kubernetes_sd_configs:
+          - role: pod
+            namespaces:
+              names: [honeydue]
+        relabel_configs:
+          - source_labels: [__meta_kubernetes_pod_label_app_kubernetes_io_name]
+            action: keep
+            regex: worker
+          - source_labels: [__meta_kubernetes_pod_container_port_number]
+            action: keep
+            regex: "6060"
+          - source_labels: [__meta_kubernetes_pod_name]
+            target_label: pod
+          - source_labels: [__meta_kubernetes_pod_node_name]
+            target_label: node
+          - target_label: service
+            replacement: worker
 
 ---
 apiVersion: v1

deploy-k3s/manifests/worker/deployment.yaml

@@ -43,6 +43,11 @@ spec:
         - name: worker
           image: IMAGE_PLACEHOLDER  # Replaced by 03-deploy.sh
           imagePullPolicy: IfNotPresent  # audit CODE-L4 — explicit; images are SHA/digest-pinned
+          ports:
+            # health + Prometheus /metrics (in-cluster only; scraped by vmagent)
+            - name: metrics
+              containerPort: 6060
+              protocol: TCP
           securityContext:
             allowPrivilegeEscalation: false
             readOnlyRootFilesystem: true
@@ -95,3 +100,46 @@ spec:
         - name: tmp
           emptyDir:
             sizeLimit: 64Mi
+---
+# Allow vmagent to scrape the worker's /metrics on :6060 (default-deny-all is in
+# force; the worker otherwise receives no ingress). Additive — see node-exporter.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-ingress-to-worker-metrics
+  namespace: honeydue
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: worker
+  policyTypes:
+    - Ingress
+  ingress:
+    - from:
+        - podSelector:
+            matchLabels:
+              app.kubernetes.io/name: vmagent
+      ports:
+        - port: 6060
+          protocol: TCP
+---
+# vmagent's base egress policy only opens :8000/:8080 to the pod CIDR; this
+# additive policy opens :6060 for the worker scrape (leaves the base untouched).
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-egress-from-vmagent-to-worker
+  namespace: honeydue
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: vmagent
+  policyTypes:
+    - Egress
+  egress:
+    - to:
+        - ipBlock:
+            cidr: 10.42.0.0/16
+      ports:
+        - port: 6060
+          protocol: TCP