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/app/admin/email-templates/page.tsx

@@ -4,6 +4,7 @@ import {
 	deleteEmailTemplate,
 	updateEmailTemplate,
 } from "@/actions/admin-email-templates";
+import { Button } from "@/components/ui/button";
 import { prisma } from "@/lib/prisma";
 import { redirect } from "next/navigation";
 import { canAccess, getAdminContext, PERMS } from "@/lib/permissions";
@@ -69,9 +70,9 @@ export default async function AdminEmailTemplates() {
 					rows={5}
 					className="w-full resize-y mb-3"
 				/>
-				<button type="submit" className="btn btn-primary">
+				<Button type="submit" variant="default">
 					{t("create")}
-				</button>
+				</Button>
 			</form>
 
 			<div className="grid">
@@ -116,9 +117,9 @@ export default async function AdminEmailTemplates() {
 									className="w-full resize-y mb-2"
 								/>
 								<div className="flex gap-2 items-center">
-									<button type="submit" className="btn btn-primary">
+									<Button type="submit" variant="default">
 										{t("save")}
-									</button>
+									</Button>
 									{template.updatedAt ? (
 										<span className="text-xs theme-text-muted dark:theme-text-muted">
 											{t("updated", {
@@ -133,9 +134,9 @@ export default async function AdminEmailTemplates() {
 							</form>
 							<form action={deleteEmailTemplate} className="mt-4">
 								<input type="hidden" name="id" value={id} />
-								<button type="submit" className="btn btn-danger">
+								<Button type="submit" variant="destructive">
 									{t("delete")}
-								</button>
+								</Button>
 							</form>
 						</div>
 					);