Replace String() calls with .toString()/.toLocaleString() per ast-grep rule

- Add formatError() helper in CLI to safely handle unknown error types
- Add uniqueTestId() helper for generating unique test identifiers
- Replace String(id) with id.toString() for database ID conversions
- Replace String(n) with n.toLocaleString() for user-facing number formatting
- Fix TypeScript errors in test files (undefined checks, unused variables)
- Update lint commands to include ast-grep scanning

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api-server/src/utils/webauthn.ts

@@ -162,7 +162,7 @@ export const verifyRegistration = async (
   const challengeRow = await db
     .selectFrom("webauthn_challenges")
     .select("options")
-    .where("id", "=", String(challengeId))
+    .where("id", "=", challengeId.toString())
     .executeTakeFirst();
 
   if (!challengeRow) {
@@ -189,7 +189,7 @@ export const verifyRegistration = async (
     // Always delete the challenge
     await db
       .deleteFrom("webauthn_challenges")
-      .where("id", "=", String(challengeId))
+      .where("id", "=", challengeId.toString())
       .execute();
   }
 
@@ -278,7 +278,7 @@ export const verifyAuthentication = async (
   const challengeRow = await db
     .selectFrom("webauthn_challenges")
     .select("options")
-    .where("id", "=", String(challengeId))
+    .where("id", "=", challengeId.toString())
     .executeTakeFirst();
 
   if (!challengeRow) {
@@ -321,7 +321,7 @@ export const verifyAuthentication = async (
         counter: verification.authenticationInfo.newCounter.toString(),
         last_used_at: new Date(),
       })
-      .where("id", "=", String(passkey.id))
+      .where("id", "=", passkey.id.toString())
       .execute();
 
     return true;
@@ -329,7 +329,7 @@ export const verifyAuthentication = async (
     // Always delete the challenge
     await db
       .deleteFrom("webauthn_challenges")
-      .where("id", "=", String(challengeId))
+      .where("id", "=", challengeId.toString())
       .execute();
   }
 };