feat: improve subscription gesture handling

[Itodo-S]

Summary

• add reusable swipe, long-press, validation, and debug helpers for subscription cards
• wrap the app in the gesture handler root and surface gesture hints in the home screen
• add gesture validation tests for swipe thresholds, priority, and debug labels

Closes #235

Verification

• local source review of the updated gesture flows
• no automated test run was possible in this environment because project dependencies are not installed locally

[drips-wave]

@Itodo-S Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits