feat(tasks): add pomodoro to an existing task from the dialog

[MegaBadCoder]

Summary

• Task detail shows a Помодоро switch even when the task has no config
• On → PUT /tasks/:id/pomodoro-config (creates config; round count fits durationMinutes)
• Off → DELETE the config
• Dialog reads optimistic isPomodoroTask on selectedTask

Test plan

• Open a non-pomodoro task → switch on → settings appear, timer play works
• 60-minute task → 2×25 rounds
• Task with no duration → 4×25
• Switch off → pomodoro section collapses, badge gone from the list
• Overdue task stays read-only (no switch)

Made with Cursor