fix(FN-1029): fix flaky test failures and keyboard event forwarding

- Add onKeyDown handler to CustomModelDropdown portal container for keyboard event forwarding
- Wrap SettingsModal empty state assertions in waitFor for async test stability
- Extract rate limiter state for proper test isolation in routes tests
- Add reconcileProjectStatuses to CentralCore mock for consistent test setup
- Improve /api/ai/summarize-title rate limiting with per-test isolation

packages/dashboard/app/components/CustomModelDropdown.tsx

@@ -440,6 +440,7 @@ export function CustomModelDropdown({
       className="model-combobox-dropdown model-combobox-dropdown--portal"
       role="listbox"
       data-testid="model-combobox-portal"
+      onKeyDown={handleKeyDown}
       style={{
         top: `${dropdownPosition.top}px`,
         left: `${dropdownPosition.left}px`,