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/cli/src/routes/admin/complete-login.ts

@@ -2,6 +2,7 @@ import type { LocalContext } from "../../context.js";
 import { ORPCError } from "@orpc/client";
 import { buildCommand } from "@stricli/core";
 import { createApiClient } from "../../utils/api-client.js";
+import { formatError } from "../../utils/format-error.js";
 
 interface CompleteLoginFlags {
   email: string;
@@ -21,12 +22,10 @@ async function completeLogin(
     console.log(`Completed login request for: ${flags.email}`);
   } catch (error) {
     if (error instanceof ORPCError) {
-      console.error(`Error [${String(error.code)}]:`, error.message);
+      // eslint-disable-next-line @typescript-eslint/restrict-template-expressions -- ORPCError.code is typed as any
+      console.error(`Error [${error.code}]:`, error.message);
     } else {
-      console.error(
-        "Error:",
-        error instanceof Error ? error.message : String(error),
-      );
+      console.error("Error:", formatError(error));
     }
     this.process.exit(1);
   }