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/gateway/ui/pages/sessions.js

@@ -14,11 +14,11 @@ let _client = null;
 let _el = null;
 
 async function loadSessionList() {
-  if (!_client || !_el) return;
+  if (!_client || !_el) {return;}
 
   const listContainer = _el.querySelector('#sessions-list');
   const detailContainer = _el.querySelector('#session-detail');
-  if (detailContainer) detailContainer.innerHTML = '';
+  if (detailContainer) {detailContainer.innerHTML = '';}
 
   try {
     const result = await _client.call('sessions.list');
@@ -78,7 +78,7 @@ async function loadSessionList() {
 
 async function viewSession(sessionId) {
   const detailContainer = _el.querySelector('#session-detail');
-  if (!detailContainer) return;
+  if (!detailContainer) {return;}
 
   detailContainer.innerHTML = '<div class="empty-state"><span class="spinner"></span> Loading...</div>';