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>

packages/common/src/format-date.ts

@@ -95,11 +95,11 @@ export function formatRelativeDate(
     return "Yesterday";
   }
   if (diffDays < 7) {
-    return `${String(diffDays)} days ago`;
+    return `${diffDays.toLocaleString()} days ago`;
   }
   if (diffDays < 30) {
     const weeks = Math.floor(diffDays / 7);
-    return weeks === 1 ? "1 week ago" : `${String(weeks)} weeks ago`;
+    return weeks === 1 ? "1 week ago" : `${weeks.toLocaleString()} weeks ago`;
   }
 
   // For older dates, show the actual date

packages/testing/test-helpers/src/index.ts

@@ -16,3 +16,4 @@ export {
   truncateAllTables,
 } from "./test-db.js";
 export { withTestTransaction } from "./test-transaction.js";
+export { uniqueTestId } from "./test-utils.js";

packages/testing/test-helpers/src/test-db.ts

@@ -9,6 +9,7 @@ import { join } from "node:path";
 import { createDb } from "@reviq/db";
 import { sql } from "kysely";
 import pg from "pg";
+import { uniqueTestId } from "./test-utils.js";
 
 const { Client } = pg;
 
@@ -192,7 +193,7 @@ export async function runMigrations(): Promise<void> {
   if (exitCode !== 0) {
     const stderr = await new Response(proc.stderr).text();
     throw new Error(
-      `Migration failed with code ${String(exitCode)}: ${stderr}`,
+      `Migration failed with code ${exitCode.toString()}: ${stderr}`,
     );
   }
 }
@@ -224,7 +225,7 @@ export async function createTestUser(
     isSuperuser: boolean;
   }> = {},
 ): Promise<{ id: number; email: string }> {
-  const email = overrides.email ?? `test-${String(Date.now())}@example.com`;
+  const email = overrides.email ?? `test-${uniqueTestId()}@example.com`;
 
   const result = await db
     .insertInto("users")

packages/testing/test-helpers/src/test-utils.ts

@@ -0,0 +1,15 @@
+/**
+ * Test utility functions
+ */
+
+/**
+ * Generates a unique test ID using timestamp and random string.
+ * Useful for creating unique emails, slugs, tokens, etc. in tests.
+ *
+ * @example
+ * const email = `user-${uniqueTestId()}@example.com`
+ * const slug = `org-${uniqueTestId()}`
+ */
+export function uniqueTestId(): string {
+  return `${Date.now().toString()}-${Math.random().toString(36).slice(2, 8)}`;
+}

packages/utils/src/hash-password.ts

@@ -63,7 +63,7 @@ export const hashPassword = async (password: string): Promise<string> => {
   const saltB64 = toBase64(salt.buffer);
   const hashB64 = toBase64(derivedBits);
 
-  return `$${ALGORITHM}$${String(ITERATIONS)}$${saltB64}$${hashB64}`;
+  return `$${ALGORITHM}$${ITERATIONS.toString()}$${saltB64}$${hashB64}`;
 };
 
 export const verifyPassword = async (