feat(apps): forte-drop web + mcp argocd apps (prod) (#18)

## Summary

ArgoCD Applications + Keycloak clients + sealed secret for forte-drop **web + mcp** (PROD).

## What changed

- **forte-drop** + **forte-drop-mcp** ArgoCD Applications (two-source: forte-helm chart + helm-prod-values).
- **namespace.yaml** — explicit `forte-drop` Namespace at sync-wave -1, `Prune=false` (avoids first-sync race for namespaced resources; doesn't cascade-delete on base removal).
- **keycloak-client-forte-drop** + **keycloak-client-forte-drop-mcp** — labeled config Secrets; the registrar creates the OIDC clients in the `forte` realm within ~2 min.
- **forte-drop-secrets** SealedSecret — UpCloud S3 creds (existing drops bucket) + PG creds + PASSWORD_GATE_SECRET. Consumed by both deployments + the pg-backup CronJob.
- **forte-drop-web PDB** — minAvailable 1 (selector verified against the live forteapp chart's pod labels).
- Wired into `apps/overlays/upc-dev` (NOT base → stays out of upc-prod).

## Post-merge manual step (one-time)

`auth-oidc` SealedSecret for the web sidecar is still commented out — it needs the `client-secret` the Keycloak registrar writes to `forte-drop-oidc-credentials` after first sync:

```bash
CLIENT_SECRET=$(kubectl -n forte-drop get secret forte-drop-oidc-credentials -o jsonpath='{.data.client-secret}' | base64 -d)
kubectl create secret generic auth-oidc -n forte-drop \
  --from-literal=client-secret="$CLIENT_SECRET" \
  --from-literal=cookie-secret="$(openssl rand -hex 32)" \
  --dry-run=client -o yaml > private/auth-oidc.yaml
kubeseal --format=yaml --controller-name=sealed-secrets-controller --controller-namespace=kube-system \
  < private/auth-oidc.yaml > apps/base/forte-drop/auth-oidc-sealed.yaml
# uncomment in kustomization, commit, push
```

## Depends on

- launchpad PR #17 (postgres + namespace via CreateNamespace).
- helm-prod-values forte-drop PR (values).

## Review

- [x] codex: namespace first-sync race → fixed (explicit namespace, sync-wave -1).
- [x] Keycloak registrar unblocked (stale chibisafe/minio config secrets removed; registrar green).

🤖 Generated with Claude Code

Co-authored-by: Sten <sten@Sten-sin-MacBook-Pro.local>
Co-authored-by: Sten <sten@Mac.domain_not_set.invalid>
Co-authored-by: Danijel Simeunovic <danijel.simeunovic@fortedigital.com>
Reviewed-on: #18
Reviewed-by: Danijel Simeunovic <danijel.simeunovic@fortedigital.com>

apps/overlays/upc-dev/forte-drop-postgresql/resources/postgresql.yaml

@@ -0,0 +1,105 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: forte-drop-postgresql
+  namespace: forte-drop
+  labels:
+    app.kubernetes.io/name: postgresql
+    app.kubernetes.io/instance: forte-drop
+    app.kubernetes.io/component: database
+spec:
+  type: ClusterIP
+  ports:
+  - name: tcp-postgresql
+    port: 5432
+    targetPort: tcp-postgresql
+  selector:
+    app.kubernetes.io/name: postgresql
+    app.kubernetes.io/instance: forte-drop
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: forte-drop-postgresql
+  namespace: forte-drop
+  labels:
+    app.kubernetes.io/name: postgresql
+    app.kubernetes.io/instance: forte-drop
+    app.kubernetes.io/component: database
+spec:
+  serviceName: forte-drop-postgresql
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: postgresql
+      app.kubernetes.io/instance: forte-drop
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: postgresql
+        app.kubernetes.io/instance: forte-drop
+        app.kubernetes.io/component: database
+    spec:
+      containers:
+      - name: postgresql
+        image: postgres:16-alpine
+        # NOTE: no securityContext. The official postgres image's entrypoint must
+        # start as root to chown a fresh /var/lib/postgresql/data, then drops to
+        # the postgres user (uid 70 in alpine) via gosu. Forcing runAsNonRoot here
+        # breaks initdb on a fresh PVC. Matches the vaultwarden-postgresql pattern.
+        ports:
+        - name: tcp-postgresql
+          containerPort: 5432
+        env:
+        - name: POSTGRES_USER
+          valueFrom:
+            secretKeyRef:
+              name: forte-drop-pg-creds
+              key: pgusername
+        - name: POSTGRES_PASSWORD
+          valueFrom:
+            secretKeyRef:
+              name: forte-drop-pg-creds
+              key: pgpassword
+        - name: POSTGRES_DB
+          value: drops
+        - name: PGDATA
+          value: /var/lib/postgresql/data/pgdata
+        volumeMounts:
+        - name: data
+          mountPath: /var/lib/postgresql/data
+        livenessProbe:
+          exec:
+            command:
+            - sh
+            - -c
+            - pg_isready -U "$POSTGRES_USER" -d drops
+          initialDelaySeconds: 30
+          periodSeconds: 10
+        readinessProbe:
+          exec:
+            command:
+            - sh
+            - -c
+            - pg_isready -U "$POSTGRES_USER" -d drops
+          initialDelaySeconds: 5
+          periodSeconds: 5
+        resources:
+          requests:
+            cpu: 100m
+            memory: 256Mi
+          limits:
+            cpu: 500m
+            memory: 512Mi
+  volumeClaimTemplates:
+  - metadata:
+      name: data
+      annotations:
+        argocd.argoproj.io/sync-options: Prune=false,Delete=false
+    spec:
+      accessModes:
+      - ReadWriteOnce
+      storageClassName: upcloud-block-storage-maxiops
+      resources:
+        requests:
+          storage: 5Gi