[Refactor] Unify Roomote GitHub bot-identity helpers

[roomote-roomote]

Created by Roomote. Follow up by mentioning @openmote or in the web UI.

Important

Roomote does not generally accept unsolicited community pull requests. Unless a maintainer invited this PR in an issue or discussion, it will likely be closed without review. A well-written issue is the best way to contribute.

Related issue

Internal Roomote maintenance (no public issue). Collapsing partially divergent GitHub bot-identity helpers left behind after database-configured app slug support.

Why this PR exists

• A maintainer explicitly invited this PR in the linked issue or discussion
• I am a maintainer / this is internal Roomote work

Reviewer/automation managed logins, cloud-agent issue-comment author checks, and runtime @roomote/github identity checks no longer shared one policy, so deployments could recognize bot logins inconsistently (especially roomote-dev, custom configured slugs, and roomote-* prefix forms).

What changed

• One pure identity policy owned in shared types: hosted base slugs (roomote, roomote-dev) plus configured slug; exact managed-login list for finite allowlists; full match helper that also accepts open roomote-* / app/roomote-* forms
• Runtime isRoomoteGitHubLogin is a thin wrapper over that policy using the effective app slug
• Cloud-agents deleted its private reimplementation and calls the shared comment-author helper
• Reviewer collaborator allowlists intentionally stay on the exact-login subset derived from the same base slugs (not open-ended prefixes)

No intended user-facing product change. Allowlist generation now also includes hosted roomote-dev exact logins so it stays aligned with identity checks.

How it was tested

• New pure-policy unit tests for custom slug, roomote-dev, prefix forms, and exact managed logins
• Runtime schema tests covering prefix recognition and database-configured slug resolution
• pnpm lint and pnpm check-types passed

Checklist

• The PR title follows the repo convention: [Fix], [Feat], [Improve], [Refactor], [Docs], or [Chore] followed by a user-facing description
• This PR is small and scoped to one change
• pnpm lint and pnpm check-types pass locally
• I added tests or included a clear manual validation note above
• I removed secrets, tokens, private keys, and customer data from code, logs, and screenshots
• If this change should appear in the changelog, I ran pnpm changeset

[roomote-roomote]

No code issues found. See task