Checkpoint Sprite Factory 1.2.2 before staged rebuild

[Awetspoon]

What changed

• Captures the current working Sprite Factory app before the planned staged rebuild.
• Consolidates preset handling, detected edit baselines, output-size controls, Final preview refresh, batch/export behavior, Web Sources improvements, UI cleanup, packaging assets, and documentation.
• Removes obsolete duplicate coordinators, encoding window code, and duplicate root icon files.

Why

This creates a tested recovery point so the next architecture rebuild can proceed section by section without risking the current working application.

Validation

• 349 automated tests passing
• Python compilation passing
• Repository and packaging audit passing
• git diff --cached --check passing