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/lib/action-helper.ts

@@ -0,0 +1,29 @@
+import { logger } from "@/lib/logger";
+
+export interface ActionResult<T = void> {
+  success: boolean;
+  data?: T;
+  error?: string;
+}
+
+export async function wrapAction<T>(
+  fn: () => Promise<T>,
+  actionName: string,
+): Promise<ActionResult<T>> {
+  try {
+    const data = await fn();
+    return { success: true, data };
+  } catch (err) {
+    const message = err instanceof Error ? err.message : "Unknown error";
+    logger.error(`Action failed: ${actionName}`, {
+      action: actionName,
+      error: message,
+    });
+    return { success: false, error: message };
+  }
+}
+
+export function actionError(actionName: string, message: string): ActionResult<never> {
+  logger.error(`Action failed: ${actionName}`, { action: actionName, error: message });
+  return { success: false, error: message };
+}