Add Gitea / Forgejo Issues backlog manager

[SimonBlancoE]

Summary

Adds a new Gitea / Forgejo Issues backlog manager for sandcastle init, powered by the tea CLI.

This lets users scaffold the existing Sandcastle issue-based workflows against Gitea-compatible forges, including Forgejo, without manually rewriting generated prompts or sandbox setup.

What changed

• Adds a gitea-issues backlog manager option.

• Installs the tea CLI in generated Dockerfile/Containerfile output.

• Generates .sandcastle/.env.example entries for:

  GITEA_SERVER_URL=
  GITEA_ACCESS_TOKEN=

• Runs tea login inside the sandbox at startup, after .sandcastle/.env has been loaded.

• Substitutes generated prompt commands for listing, viewing, commenting on, and closing issues via tea.

• Supports optional Sandcastle label creation for Gitea / Forgejo.

• Keeps the existing GitHub Issues and Beads flows intact.

• Documents the new backlog manager and adds a patch changeset.

Setup note

After running sandcastle init with Gitea / Forgejo Issues, users need to set these values in .sandcastle/.env:

GITEA_SERVER_URL=https://your-forgejo-or-gitea-instance
GITEA_ACCESS_TOKEN=your-personal-access-token

The generated sandbox setup uses those values to authenticate tea before the agent reads or updates issues.

Manual testing

I manually tested this successfully against a project hosted on Forgejo. The generated setup was able to authenticate with tea, read issues from the Forgejo project, and use the generated workflow as the issue tracker backend.

Test plan

• npx vitest run src/InitService.test.ts
• npx prettier --check README.md src/InitService.ts src/InitService.test.ts src/cli.ts .changeset/gitea-forgejo-tea-backlog.md
• git diff --check origin/main..HEAD

Notes

I found no CONTRIBUTING.md or pull request template in the repository. I followed the local repository guidance in CLAUDE.md by adding a patch changeset and updating the README for the user-facing behavior.

[vercel]

Someone is attempting to deploy a commit to the Matt Pocock's projects Team on Vercel.

A member of the Team first needs to authorize it.

[sti0]

Awesome. There is also a seperate fj cli for Forgejo. Maybe split between Gitea and Forgejo.