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/kanban/KanbanBoard.test.tsx

@@ -226,8 +226,8 @@ describe("KanbanBoard", (): void => {
       const fetchMock = global.fetch as ReturnType<typeof vi.fn>;
       fetchMock.mockResolvedValueOnce({
         ok: true,
-        json: () => ({ status: TaskStatus.IN_PROGRESS }),
-      } as Response);
+        json: () => Promise.resolve({ status: TaskStatus.IN_PROGRESS }),
+      } as unknown as Response);
 
       render(<KanbanBoard tasks={mockTasks} onStatusChange={mockOnStatusChange} />);
 

apps/web/src/components/kanban/KanbanBoard.tsx

@@ -110,7 +110,7 @@ export function KanbanBoard({ tasks, onStatusChange }: KanbanBoardProps): React.
         if (onStatusChange) {
           onStatusChange(taskId, newStatus);
         }
-      } catch (_error) {
+      } catch (error) {
         console.error("Error updating task status:", error);
         // TODO: Show error toast/notification
       }