chore: remediate pygienium audit findings

Dead code: 77 verified-unused exports, files (BackArrow, MenuBars,
cookies.ts, db/create.ts, schemas/comment.ts, security-headers.ts) and
12 unused dependencies removed
Comments: ~370 RESTATE comments stripped across 53 files; 2 verbose
blocks tightened; dead commented-out config removed
Complexity: bulkUpsert extracted into 11 per-entity helpers (CCN 156->~10);
login formHandler split into 3 submitters (CCN 63->~5); account page render
split into 8 section components (CCN 40); updatePost SQL builder rebuilt;
assert*Owned consolidated behind generic assertOwnedBy
Defensive guards: 4 redundant rethrow/nullish guards removed

src/components/ContactForm.tsx

@@ -144,7 +144,6 @@ const sendContactEmail = action(async (formData: FormData) => {
 
   const { env } = await import("~/env/server");
 
-  // Verify Cloudflare Turnstile token
   const turnstileValid = await verifyTurnstileToken(
     turnstileToken,
     env.TURNSTILE_SECRET_KEY,
@@ -252,7 +251,6 @@ export function ContactForm(props: ContactFormProps) {
 
   const [searchParams] = useSearchParams();
 
-  // Load server data using createAsync
   const contactData = createAsync(() => getContactData(), {
     deferStream: true
   });
@@ -350,7 +348,6 @@ export function ContactForm(props: ContactFormProps) {
     const message = formData.get("message") as string;
 
     if (name && email && message) {
-      // Get fresh Turnstile token
       let currentToken = turnstileToken();
       if (
         !currentToken &&
@@ -388,7 +385,6 @@ export function ContactForm(props: ContactFormProps) {
           setError("");
           form.reset();
 
-          // Reset Turnstile widget
           if (typeof window !== "undefined" && (window as any).turnstile) {
             const widgetEl = document.getElementById("turnstile-widget-1");
             if (widgetEl) {