feat: add data-testid attributes to RouteFilter inputs for test interactions

- Add data-testid to city autocomplete dropdown inputs via pt.input property
- Add data-testid to departure/arrival date calendar inputs via pt.input property
- Add data-testid to swap cities button for test detection
- Both wrapper and input elements now have testids for test selectors
- Ensures Cypress tests can find and interact with form elements

.claude/scheduled_tasks.lock

@@ -0,0 +1 @@
+{"sessionId":"c5ca7b97-b8fb-464c-9bb2-52aa0dc335be","pid":44074,"acquiredAt":1775396071197}