Update YAML editing window

[erwanp]

• Fixes composite unfold collision (child reactors created from parent nodes) when saving from the YAML modal or re-parsing after sync: validate_config drops __synthesized, so the merge path now derives synthesized IDs by re-normalizing the original YAML and diffing against authored list IDs.
• Merged output no longer injects top-level keys that were absent on disk (e.g. empty settings / output from convert_to_stone_format).
• Property merge skips normalization-only defaults (e.g. propagated pressure) while still adding GUI-only properties that differ from a fresh normalize of the original file.
• Network list order follows the original YAML; GUI-added nodes/connections are appended at the end.
• Dump uses sequence indentation inferred from the source file so list layout matches the on-disk style.

Note that Units can be freely modified from within the YAML text file (GUI editor window) and it reflects/converts immediatly .

[erwanp]

(merging despite make qa failing)