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/auth/status.ts

@@ -2,6 +2,7 @@ import type { LocalContext } from "../../context.js";
 import { buildCommand } from "@stricli/core";
 import { createApiClient } from "../../utils/api-client.js";
 import { getConfigPath, readConfig } from "../../utils/config.js";
+import { formatError } from "../../utils/format-error.js";
 import { TOKEN_PREFIX } from "../../utils/token.js";
 
 function formatDate(date: Date): string {
@@ -14,19 +15,19 @@ function formatRelativeTime(date: Date): string {
   const diffDays = Math.floor(diffMs / (1000 * 60 * 60 * 24));
 
   if (diffDays < 0) {
-    return `${String(Math.abs(diffDays))} days ago`;
+    return `${Math.abs(diffDays).toLocaleString()} days ago`;
   }
   if (diffDays === 0) {
     const diffHours = Math.floor(diffMs / (1000 * 60 * 60));
     if (diffHours <= 0) {
       return "expired";
     }
-    return `in ${String(diffHours)} hours`;
+    return `in ${diffHours.toLocaleString()} hours`;
   }
   if (diffDays === 1) {
     return "tomorrow";
   }
-  return `in ${String(diffDays)} days`;
+  return `in ${diffDays.toLocaleString()} days`;
 }
 
 async function status(this: LocalContext): Promise<void> {
@@ -96,9 +97,7 @@ async function status(this: LocalContext): Promise<void> {
       );
     }
   } catch (error) {
-    console.log(
-      `  Error: ${error instanceof Error ? error.message : String(error)}`,
-    );
+    console.log(`  Error: ${formatError(error)}`);
     console.log(
       "\n  Unable to connect to API. Local credentials may be invalid.",
     );