Update zone ID on config subentry rename

[lnagel]

When a zone config subentry is renamed via Home Assistant's native rename action, this change ensures:

• Zone ID (subentry.data["id"]) is updated to match the new slugified name
• Entity registry entries are updated with new unique_id values
• Device registry identifier is updated
• Stored state data is migrated from old zone ID to new zone ID

The migration is performed during entry setup by comparing subentry.title with subentry.data["name"]. If they differ, the zone was renamed and migration is triggered.

Includes comprehensive tests for:

• Zone ID update
• Entity unique_id updates
• Device identifier updates
• Stored state migration
• Conflict detection when new ID already exists
• No-op when slugified name matches existing ID

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.09%. Comparing base (c141682) to head (4448acc).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #29      +/-   ##
==========================================
+ Coverage   95.01%   95.09%   +0.08%     
==========================================
  Files          20       20              
  Lines        1645     1673      +28     
  Branches      251      258       +7     
==========================================
+ Hits         1563     1591      +28     
  Misses         45       45              
  Partials       37       37              

Files with missing lines	Coverage Δ
custom_components/ufh_controller/__init__.py	85.71% <100.00%> (+5.19%)	⬆️