fix: resolve all ESLint warnings (setState in useEffect)

Suppress 3 react-hooks/set-state-in-effect warnings with targeted
eslint-disable comments. These are intentional patterns:
- ChatInput: restore draft text on session switch
- MessageSearch: reset active index on query change
- ToolCall: sync open state with global collapse/expand toggle

Lint now passes with 0 errors and 0 warnings.

src/components/MessageSearch.tsx

@@ -28,7 +28,7 @@ export function MessageSearch({ open, onClose, onSearch, matchCount }: Props) {
 
   // Reset active index when query changes
   useEffect(() => {
-    setActiveIndex(0);
+    setActiveIndex(0); // eslint-disable-line react-hooks/set-state-in-effect -- intentional: reset index on query change
   }, [query]);
 
   const navigate = useCallback((dir: 1 | -1) => {