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/widgets/__tests__/CalendarWidget.test.tsx

@@ -15,9 +15,12 @@ describe("CalendarWidget", (): void => {
   });
 
   it("should render loading state initially", (): void => {
-    vi.mocked(global.fetch).mockImplementation(() => new Promise(() => {
-      // Intentionally never resolves to keep loading state
-    }));
+    vi.mocked(global.fetch).mockImplementation(
+      () =>
+        new Promise(() => {
+          // Intentionally never resolves to keep loading state
+        })
+    );
 
     render(<CalendarWidget id="calendar-1" />);
 
@@ -42,8 +45,8 @@ describe("CalendarWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockEvents,
-    });
+      json: () => Promise.resolve(mockEvents),
+    } as unknown as Response);
 
     render(<CalendarWidget id="calendar-1" />);
 
@@ -56,8 +59,8 @@ describe("CalendarWidget", (): void => {
   it("should handle empty event list", async (): Promise<void> => {
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => [],
-    });
+      json: () => Promise.resolve([]),
+    } as unknown as Response);
 
     render(<CalendarWidget id="calendar-1" />);
 
@@ -91,8 +94,8 @@ describe("CalendarWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockEvents,
-    });
+      json: () => Promise.resolve(mockEvents),
+    } as unknown as Response);
 
     render(<CalendarWidget id="calendar-1" />);
 
@@ -105,8 +108,8 @@ describe("CalendarWidget", (): void => {
   it("should display current date", async (): Promise<void> => {
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => [],
-    });
+      json: () => Promise.resolve([]),
+    } as unknown as Response);
 
     render(<CalendarWidget id="calendar-1" />);