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 <noreply@anthropic.com>

apps/web/src/components/widgets/__tests__/TasksWidget.test.tsx

@@ -32,8 +32,8 @@ describe("TasksWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockTasks,
-    });
+      json: () => Promise.resolve(mockTasks),
+    } as unknown as Response);
 
     render(<TasksWidget id="tasks-1" />);
 
@@ -52,8 +52,8 @@ describe("TasksWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockTasks,
-    });
+      json: () => Promise.resolve(mockTasks),
+    } as unknown as Response);
 
     render(<TasksWidget id="tasks-1" />);
 
@@ -66,8 +66,8 @@ describe("TasksWidget", (): void => {
   it("should handle empty task list", async (): Promise<void> => {
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => [],
-    });
+      json: () => Promise.resolve([]),
+    } as unknown as Response);
 
     render(<TasksWidget id="tasks-1" />);
 
@@ -93,8 +93,8 @@ describe("TasksWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockTasks,
-    });
+      json: () => Promise.resolve(mockTasks),
+    } as unknown as Response);
 
     render(<TasksWidget id="tasks-1" />);
 
@@ -114,8 +114,8 @@ describe("TasksWidget", (): void => {
 
     vi.mocked(global.fetch).mockResolvedValueOnce({
       ok: true,
-      json: () => mockTasks,
-    });
+      json: () => Promise.resolve(mockTasks),
+    } as unknown as Response);
 
     render(<TasksWidget id="tasks-1" />);