refactor: full codebase overhaul — dead code removal, env validation, logger migration, date consolidation, Prisma schema cleanup, button consistency, useEffect deps, test coverage

- env.ts: added 10 missing Zod-validated env vars (imager, paypal currency, argon2/bcrypt params)
- Migrated 6 modules from process.env to validated env.* (auth, proxy-auth, paypal, password, redis, imager, moderation, alert, logger)
- Replaced console.warn/error with pino logger in 9 server-side modules
- Removed 50+ dead exports (SWF wrappers, coalesceHotelName, signIn, isStaff re-export, formatTimestamp, Skeleton/SkeletonCard, 4 unused housekeeping sections)
- Consolidated date formatting: 28 files migrated to shared formatDate() from @/lib/format-date
- Wired 4 radio/settings API routes through cached siteSettings service instead of raw Prisma queries
- Added getMany()/getAll() helpers to SiteSettings service
- Removed 88 dead Prisma model definitions (schema 2763→1846 lines)
- Created admin action-helper.ts with wrapAction() for standardized error handling
- Fixed useEffect dependency arrays in 4 data-heavy components
- Replaced raw btn CSS classes with shadcn Button component across admin pages
- Stripped dead i18n namespaces (common, pages.client) from all 22 translation files
- Removed 2 dead scripts (create-release.sh, check-local-imports.ts)
- Fixed knip.json configuration
- Added 7 new test suites: format-date, paypal, moderation, alert, webhook, action-helper, and fixed password.test.ts for env mocking
- All 358 tests passing across 72 test files
- TypeScript: 0 errors

src/messages/da.json

@@ -36,11 +36,6 @@
   "footer": {
     "copyright": "© {year} - {hotel} er et undervisningsprojekt uden fortjeneste"
   },
-  "common": {
-    "language": "Sprog",
-    "lightMode": "Lys tilstand",
-    "darkMode": "Mørk tilstand"
-  },
   "pages": {
     "staff": {
       "title": "Personale",
@@ -189,7 +184,7 @@
       "newsTitle": "Seneste nyt",
       "newsSubtitle": "Frisk fra hotellet",
       "allNews": "Alle nyheder →",
-			"allUsers": "Fællesskab →",
+      "allUsers": "Fællesskab →",
       "noArticles": "Ingen artikler endnu.",
       "noPhotos": "Ingen billeder endnu.",
       "noUsers": "Ingen brugere online",
@@ -650,21 +645,6 @@
         "error": "Something went wrong. Please try again."
       }
     },
-    "client": {
-      "title": "Nitro klient",
-      "loading": "Indlæser klient...",
-      "generatingTicket": "Genererer SSO-billet...",
-      "connected": "Forbundet",
-      "welcome": "Velkommen til {hotel}",
-      "openingClient": "Åbner klienten i en ny fane...",
-      "fallbackLink": "Hvis den ikke åbner,",
-      "fallbackClick": "klik her",
-      "errors": {
-        "unauthorized": "Du skal være logget ind for at åbne klienten.",
-        "generic": "Kunne ikke generere SSO-billet",
-        "loginRedirect": "Log ind"
-      }
-    },
     "radioApply": {
       "title": "Ansøg om at blive Radio DJ",
       "subtitle": "Fortæl os om dig selv, og hvorfor du ville passe godt til æteren",
@@ -709,7 +689,8 @@
       "securityTitle": "Sikkerhed",
       "securitySubtitle": "To-faktor autentificering",
       "securityDescription": "Tilføj et ekstra beskyttelseslag til din konto.",
-      "twoFactorLink": "To-faktor autentificering"},
+      "twoFactorLink": "To-faktor autentificering"
+    },
     "settings2fa": {
       "backToSettings": "← Indstillinger",
       "title": "To-faktor autentificering",
@@ -731,10 +712,10 @@
       "enableIntro": "Tilføj et ekstra sikkerhedslag med en godkendelsesapp.",
       "enable": "Aktiver 2FA"
     },
-      "title": "Tilknyttede konti",
-      "subtitle": "Link en social konto, så du kan logge ind med et enkelt klik",
-      "connected": "Forbundet",
-      "unavailable": "Ikke tilgængelig",
+    "title": "Tilknyttede konti",
+    "subtitle": "Link en social konto, så du kan logge ind med et enkelt klik",
+    "connected": "Forbundet",
+    "unavailable": "Ikke tilgængelig",
     "login": {
       "title": "Log ind",
       "subtitle": "Velkommen tilbage - log ind for at komme ind på hotellet.",