style: auto-fix ESLint issues (curly braces and formatting)

- Add curly braces to all if/else/for/while statements
- Fix indentation and trailing spaces
- Auto-fixed 372 linting errors using eslint --fix
- Remaining issues are warnings only (non-null assertions, explicit any types)

src/tools/builtin/gmail.test.ts

@@ -69,8 +69,8 @@ function setupValidAuth() {
   mockExistsSync.mockReturnValue(true);
   mockReadFileSync.mockImplementation((path: unknown) => {
     const p = String(path);
-    if (p.includes('creds')) return JSON.stringify(fakeCredentials);
-    if (p.includes('token')) return JSON.stringify(fakeToken);
+    if (p.includes('creds')) {return JSON.stringify(fakeCredentials);}
+    if (p.includes('token')) {return JSON.stringify(fakeToken);}
     return '';
   });
 }