fix: add postInitApplicationSQL for pgvector, app role isn't superuser

immich-server crash-looped on "permission denied to create extension
vector" - pgvector's control file isn't marked trusted, and CNPG's
app owner role isn't superuser (enableSuperuserAccess: false).
Documents the fix for future cluster rebuilds; the live cluster
already had CREATE EXTENSION run manually via the postgres pod's
local socket.

k8s/apps/immich/db.yaml

@@ -32,6 +32,14 @@ spec:
       encoding: UTF8
       localeCollate: C
       localeCType: C
+      # CREATE EXTENSION vector requires superuser (pgvector's control file
+      # isn't marked trusted) and the "app" owner role isn't one
+      # (enableSuperuserAccess: false, repo convention) - postInitApplicationSQL
+      # runs as superuser during initdb, before the app ever connects. Only
+      # fires on a fresh bootstrap; the live cluster already had this run
+      # manually once (kubectl exec ... psql -U postgres -c 'CREATE EXTENSION').
+      postInitApplicationSQL:
+        - "CREATE EXTENSION IF NOT EXISTS vector;"
   enableSuperuserAccess: false
   resources:
     requests: { memory: "512Mi", cpu: "250m" }