feat: add rtype field support to edit task API

[Hell1213]

Description

Added rtype parameter to edit task flow for API completeness. RType is read-only and automatically managed by taskwarrior via recur field.

• Contributes to: Make Task Model Fields Editable on Frontend and Backend #166

Checklist

• Ran npx prettier --write . (for formatting)
• Ran gofmt -w . (for Go backend)
• Ran npm test (for JS/TS testing)
• Added unit tests, if applicable
• Verified all tests pass
• Updated documentation, if needed

Additional Notes

Important: RType is a read-only field that cannot be directly edited by users. It is automatically set by Taskwarrior when the recur field is modified. This PR adds rtype to the API for completeness but does not execute any taskwarrior commands to modify it directly.

When the recur field is implemented in a future PR, rtype will automatically be populated by Taskwarrior.

Changes:

• Backend: Added RType field to EditTaskRequestBody, controller, and taskwarrior function
• Frontend: Added rtype parameter to editTaskOnBackend hook and all related function calls
• Tests: Updated test function signatures to include rtype parameter
• Documentation: Added comment explaining rtype is read-only

[Hell1213]

Hi @its-me-abhishek,
this PR adds proper handling for the rtype field. Since rtype is generated by Taskwarrior and depends on recur, it's kept read-only.

I'm starting work on the recur field next

[its-me-abhishek]

Closing this for now, perhaps we shall just go about displaying rtype on frontend, after recur gets added somehow. It already exists inside the Fetch Tasks endpoint hence won't be much of work. Thanks!