docs: Add maintainers guide documenting Bolt vendoring slash commands

Author: mwbrooks

.github/MAINTAINERS_GUIDE.md

@@ -0,0 +1,17 @@
+# Maintainers Guide
+
+## Using Bolt Framework Development Builds
+
+This repo vendors a pre-release build of [`slack-bolt`](https://github.com/slackapi/bolt-python) from the `main` branch. The `.whl` wheel lives in `vendor/` and is referenced by each implementation's `requirements.txt`.
+
+Two [Claude Code slash commands](https://docs.anthropic.com/en/docs/claude-code/slash-commands) are available to manage this:
+
+### `/vendor-bolt` — Update the vendored wheel
+
+Clones bolt-python `main`, builds a wheel with a local version identifier (e.g. `1.2.3+abc1234`), replaces the wheel in `vendor/`, and updates all `requirements.txt` references. Use this to pull in the latest unreleased bolt-python changes.
+
+### `/unvendor-bolt` — Switch to the published PyPI package
+
+Removes the `vendor/` directory, replaces the wheel reference in all `requirements.txt` and `pyproject.toml` files with the latest `slack-bolt` version from PyPI, and re-enables Dependabot updates. Use this when the vendored changes have been released and the repo should track the public package.
+
+Both commands leave changes uncommitted for review.