Skip rebuild/publish when planet edits are unchanged

[livid]

Summary

Clicking OK in MyPlanetEditView currently triggers expensive save/rebuild/publish work even when the user did not change anything.

Improvement

Normalize the edit form into a comparable snapshot before saving, and return early when the sheet is effectively unchanged.

This should treat default-backed values like nil vs "" or nil vs default booleans as equivalent so a no-op submit stays a no-op.

Notes

• Avatar changes should still count as real edits and continue to rebuild.
• This improvement has now been implemented locally in commit a4ef95bd.