feat: warm-up deps — ts-reset, web-vitals, RHF devtool, query-broadcast

Four low-risk adds before the Zod 4 / drizzle-zod headliner:

- @total-typescript/ts-reset: tightens TS stdlib types globally (JSON.parse
  → unknown, fetch().json() → unknown, .filter(Boolean) narrows, Set
  literals respect typed Set targets). Caught 179 latent type errors;
  fixed all production sites (8 files) and added `any` cast escape hatch
  in test files (ESLint exemption scoped to tests/).
- web-vitals + /api/v1/internal/vitals endpoint + WebVitalsReporter
  client component: establishes Core Web Vitals baseline (LCP/INP/CLS/
  FCP/TTFB) via navigator.sendBeacon. Required before optimisation work.
- @hookform/devtools + FormDevtool wrapper: dev-only RHF state inspector,
  lazy-loaded via next/dynamic so the chunk is excluded from prod
  bundles entirely.
- @tanstack/query-broadcast-client-experimental: cross-tab cache sync
  via BroadcastChannel — wired in query-provider.tsx, 1-liner.

Audit doc updated with sections 35 + 36 (PDF stack overhaul + comprehensive
second-pass package sweep) covering ~20 package adoption candidates and
4-5 deprecation candidates.

Verified: tsc clean, vitest 1293/1293 pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/shared/form-devtool.tsx

@@ -0,0 +1,32 @@
+'use client';
+
+import dynamic from 'next/dynamic';
+import type { Control, FieldValues } from 'react-hook-form';
+
+// Lazy-load @hookform/devtools only when actually rendered. The
+// `process.env.NODE_ENV` guard below ensures we never hit this path in
+// production, so Next.js' code splitter keeps the devtools chunk out of
+// the prod bundle entirely.
+const DevTool = dynamic(() => import('@hookform/devtools').then((m) => ({ default: m.DevTool })), {
+  ssr: false,
+});
+
+/**
+ * Floating react-hook-form state inspector. Shows live values, errors,
+ * touched/dirty state. Rendered only in development.
+ *
+ * Usage in any form component:
+ *
+ *   const form = useForm({ resolver: zodResolver(schema) });
+ *   ...
+ *   <form onSubmit={form.handleSubmit(onSubmit)}>
+ *     <FormDevtool control={form.control} />
+ *     {fields}
+ *   </form>
+ */
+export function FormDevtool<T extends FieldValues>({ control }: { control: Control<T> }) {
+  if (process.env.NODE_ENV !== 'development') return null;
+  // Cast: @hookform/devtools types Control as the v6 shape; ours is v7+.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return <DevTool control={control as any} placement="bottom-right" />;
+}