fix: QA audit — lint cleanup, i18n fixes, module visibility, sidebar UX

- Fix 97 lint errors → 0 (unused imports, params, variables across 40+ files)
- Fix i18n key format: colon → dot notation for next-intl compatibility
- Add missing i18n keys (routes.application, routes.home, confirm)
- Fix module visibility: sidebar now respects per-account DB features
- Fix inject function: use dot-notation keys, add collapsed:true defaults
- Fix ConfirmDialog: use useTranslations instead of hardcoded German defaults
- Fix events page: replace placeholder 'Beschreibung' with proper description
- Fix Dockerfile: add NEXT_PUBLIC_CI ARG for Docker builds
- Collapse secondary sidebar sections by default for cleaner UX

apps/web/i18n/messages/de/common.json

@@ -137,7 +137,9 @@
     "associationReporting": "Berichte",
     "associationTemplates": "Geteilte Vorlagen",
     "administration": "Administration",
-    "accountSettings": "Kontoeinstellungen"
+    "accountSettings": "Kontoeinstellungen",
+    "application": "Anwendung",
+    "home": "Startseite"
   },
   "roles": {
     "owner": {
@@ -219,5 +221,6 @@
     "title": "Konto nicht gefunden",
     "description": "Das angeforderte Konto existiert nicht oder Sie haben keine Berechtigung darauf zuzugreifen.",
     "action": "Zum Dashboard"
-  }
+  },
+  "confirm": "Bestätigen"
 }