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/procedures/me/sessions.ts

@@ -48,7 +48,7 @@ export const revokeSession = os.me.sessions.revoke
     const { sessionId } = input;
 
     // Prevent revoking current session (use logout instead)
-    if (String(sessionId) === context.session.id) {
+    if (sessionId.toString() === context.session.id) {
       throw new ORPCError("BAD_REQUEST", {
         message: "Cannot revoke current session. Use logout instead.",
       });
@@ -57,7 +57,7 @@ export const revokeSession = os.me.sessions.revoke
     const result = await context.db
       .updateTable("sessions")
       .set({ revoked_at: new Date() })
-      .where("id", "=", String(sessionId))
+      .where("id", "=", sessionId.toString())
       .where("user_id", "=", context.user.id)
       .where("revoked_at", "is", null)
       .executeTakeFirst();