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/server/audit.ts

@@ -405,7 +405,6 @@ export async function detectSuspiciousActivity(
   const currentIp = currentIpOrMinAttempts as string;
   const reasons: string[] = [];
 
-  // Check for excessive failed logins
   const failedAttempts = (await getFailedLoginAttempts(
     userId,
     "user_id",
@@ -415,7 +414,6 @@ export async function detectSuspiciousActivity(
     reasons.push(`${failedAttempts} failed login attempts in last 15 minutes`);
   }
 
-  // Check for rapid location changes (different IPs in short time)
   const recentIps = await conn.execute({
     sql: `SELECT DISTINCT ip_address FROM AuditLog 
           WHERE user_id = ? 
@@ -431,7 +429,6 @@ export async function detectSuspiciousActivity(
     );
   }
 
-  // Check for new IP if user has login history
   const ipHistory = await conn.execute({
     sql: `SELECT COUNT(*) as count FROM AuditLog 
           WHERE user_id = ?