Add /bot merge for delegated vendor profile maintainers (#15279)

* Add /bot merge for delegated vendor profile maintainers

Vendor profile PRs no longer need a maintainer with repository write access: an
account listed in the FOLDER_MERGERS variable can squash-merge a PR confined to
the folders it owns by commenting /bot merge on it. Anything reaching outside
that grant, targeting a branch other than main or release/*, or missing a green
Check profiles run is declined with a comment naming the offending files.
Grants live in the merge-delegation environment, so only an admin can change who
may merge, and MERGE_BOT_DRY_RUN stops all merging without a code change.

Check profiles now also runs on release/* pull requests; nothing else changes
for existing contributors.

* Add profile version bump to the code review checklist

Without the bump in resources/profiles/<Vendor>.json, a preset change never
reaches existing installs over the air.

AGENTS.md

@@ -56,6 +56,7 @@ ctest --test-dir ./tests/fff_print
 - Add helper functions or utilities only when existing code cannot reasonably be reused. Avoid duplication.
 - Keep code concise and clear. Manually simplify AI generated bloated codes before review.
 - Include targeted tests or documented verification for behavior changes, especially in slicing logic, profiles, formats, and GUI defaults.
+- For profile changes (`resources/profiles/<Vendor>/**`), check that `version` in the sibling `resources/profiles/<Vendor>.json` was bumped.
 - For translation changes (`localization/i18n/**/*.po`), check that recurring terms match the [Localization glossary](https://github.com/OrcaSlicer/OrcaSlicer_WIKI/blob/main/guides/localization_glossary.md) for that language.
 
 ## Localization & translations