Add penalty system for point deductions

[tempus2016]

Summary

• New Penalty data model (name, points to deduct, description, icon, optional per-child assignment)
• Full backend CRUD — storage, coordinator methods, and 4 new HA services (add_penalty, update_penalty, remove_penalty, apply_penalty)
• Penalties surfaced in sensor.taskmate_overview attributes so the card can read them
• New taskmate-penalties-card Lovelace card

How it works

1. Open the card and tap the pencil icon to enter edit mode
2. Tap New Penalty, enter a name (e.g. "Not going to bed") and the number of points to deduct, then save
3. Switch back to normal mode, select the child (tab at the top), then tap Apply on the relevant penalty
4. Points are deducted immediately, the tile flashes red, and a toast confirms the action

The deduction is logged in the activity feed as Penalty: <name> so it appears in the history.

Test plan

• Add a penalty via the card → verify it appears in the list
• Apply a penalty to a child → verify points decrease and activity log shows the deduction
• Edit a penalty name/points → verify the change is saved
• Delete a penalty → verify it's removed
• taskmate.apply_penalty service callable from HA developer tools
• All 120 existing tests pass