feat(lasuite): add calendars service deployment manifests

Add K8s manifests for calendars backend, frontend (Caddy), CalDAV
server, and Celery worker. Wire Pingora routing for cal.sunbeam.pt
with path-based backend/caldav/static splits. Add OAuth2Client for
OIDC, VaultDynamicSecret for DB credentials, VaultStaticSecret for
Django/CalDAV keys, and TLS cert coverage for the cal subdomain.
Register calendars in the integration service gaufre widget.

base/lasuite/calendars-frontend-caddyfile.yaml

@@ -0,0 +1,26 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: calendars-frontend-caddyfile
+  namespace: lasuite
+data:
+  Caddyfile: |
+    {
+      auto_https off
+      admin off
+    }
+
+    :8080 {
+      root * /srv
+      header X-Frame-Options DENY
+
+      route {
+        try_files {path} {path}.html /index.html
+        file_server
+      }
+
+      handle_errors {
+        rewrite * /404.html
+        file_server
+      }
+    }