Default manual developer docs runs to maintenance

[chubes4]

Summary

Default manual developer documentation runs to maintenance while retaining an explicit bootstrap choice.

What changed

• Added a workflow_dispatch run_kind choice with maintenance as the default and bootstrap available for intentional re-bootstrap runs.
• Updated workflow contract coverage and contributor documentation to match the corrected manual behavior.

How to test

1. Run actionlint .github/workflows/developer-docs-agent.yml .github/workflows/skills-agent.yml .github/workflows/ci.yml; expect All workflow files pass actionlint..
2. Run pnpm build; expect The repository build passes..
3. Run pnpm verify; expect Repository verification passes..
4. Run git diff --check; expect The patch contains no whitespace errors..

Compatibility

Behavioral correction limited to manual workflow dispatch: maintenance is now the default and explicit bootstrap remains available. Push behavior, writable paths, verification commands, secrets, and publication boundaries are unchanged.

Evidence

• CI expected: Build and test
• Reviewer-resolvable source evidence: Default manual developer-docs runs to maintenance #107
• actionlint: Passed
• build: Passed
• plugin-drift: Passed
• verify: Passed

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode general coding and review subagents
• Model: openai/gpt-5.6-sol
• Used for: Implemented and independently reviewed the workflow input/default, contract coverage, and contributor documentation; Chris reviews and owns the change.

Source relationships

• Closes Default manual developer-docs runs to maintenance #107