Fix detailed progress settings regressions

[tpmullan]

Summary

• Format print_done_message with {printTime} using the completed print payload time
• Honor use_M73: false when a print ends instead of always sending M73 P100
• Refresh cached plugin settings during progress updates so changed message/ETA settings are used without waiting for the next print
• Update custom message add/remove handling to mutate Knockout settings arrays instead of manually editing the DOM
• Clarify macOS multi-select wording in settings
• Run Black and Ruff over the Python code and add regression tests

Verification

• python3 -m unittest tests/test_detailedprogress.py
• uvx black .
• uvx ruff check .

Fixes #16
Fixes #29
Fixes #35
Fixes #42
Partially addresses #22
Partially addresses #51