fix: Resolve web package lint and typecheck errors

Fixes ESLint and TypeScript errors in web package to pass CI checks:

- Fixed all Quality Rails violations (14 explicit any types)
- Fixed deprecated React event types (FormEvent → SyntheticEvent)
- Fixed 26 TypeScript errors (Promise types, test mocks, HTMLElement assertions)
- Added vitest DOM matcher type definitions
- Fixed unused variables and empty functions
- Resolved 43+ additional lint errors

Typecheck: ✅ 0 errors
Lint: 542 remaining (non-blocking in CI)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

apps/web/src/components/hud/WidgetGrid.tsx

@@ -87,9 +87,9 @@ export function WidgetGrid({
     return layoutItem;
   });
 
-  const handleLayoutChange = (layout: readonly any[]) => {
+  const handleLayoutChange = (layout: readonly WidgetPlacement[]) => {
     if (onLayoutChange) {
-      onLayoutChange([...layout] as WidgetPlacement[]);
+      onLayoutChange(layout);
     }
   };