docs: create generated reference docs

[haleychaas]

Summary

• Tooling: Added typedoc + typedoc-plugin-markdown dev deps, a docs npm script, and regeneration on version (no TypeScript bump needed — 0.28
  supports our pinned 5.3.3).
• Config (typedoc.json): Uses node-slack-sdk's config, with two additions:
  • excludeExternals — without it, TypeDoc inlined the entire @slack/web-api + @slack/types surface (885 extra files / ~4.8 MB) that's already documented in node-slack-sdk. Output is now a focused 201 files of bolt's own API.
  • excludeScopesInPaths — collapses a @slack/-scoped output folder (a literal @ in URLs) to a clean path.
• Docs wiring: Renamed the hand-written reference.md → interface-reference.md (preserving the curated interface/config/errors guide) so the generated docs can own the reference slug; repointed the 6 internal anchor links that pointed at the old slug; added an autogenerated Reference category to _sidebar.json.
• CI: Added a Build docs step (Node 24.x only) to ci-build.yml that verifies generation succeeds, matching node-slack-sdk.
• MDX fix: Escaped raw generics (SlackActionMiddlewareArgs<...>) in a SlackAction JSDoc comment that broke the Docusaurus/MDX docs-site build; fixed at the source and regenerated.

Preview here: https://docs-slack-d-docs-branc-syafbh.herokuapp.com/tools/bolt-js/

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 94bab31

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.33%. Comparing base (531280a) to head (94bab31).

Additional details and impacted files

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##             main    #3053   +/-   ##
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  Coverage   94.33%   94.33%           
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  Files          43       43           
  Lines        7360     7360           
  Branches      679      679           
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  Hits         6943     6943           
  Misses        409      409           
  Partials        8        8           

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