fix(FN-1446): improve test reliability and git command TTY handling

- Fix QuickEntryBox focus restoration after task creation with proper submission state tracking
- Improve QuickEntryBox tests by using explicit promise resolution and proper afterEach cleanup with act() wrappers
- Fix TaskCard tests to use proper act() wrappers for async operations
- Add stdio: 'pipe' to all git execSync calls to prevent TTY interaction issues in CI environments
- Add test log suppression for noisy subagent and pi-claude-cli output in vitest setup

packages/dashboard/app/components/__tests__/QuickEntryBox.test.tsx

@@ -218,8 +218,10 @@ describe("QuickEntryBox", () => {
     });
   });
 
-  afterEach(() => {
-    vi.runOnlyPendingTimers();
+  afterEach(async () => {
+    await act(async () => {
+      vi.runOnlyPendingTimers();
+    });
     vi.useRealTimers();
     localStorage.clear();
   });