Add long-lived API tokens with three permission scopes (read-only,
deploy-only, full-admin) for CI/CD pipelines, scripts, and automation.
- Database: api_tokens table with SHA-256 hashed storage
- Auth: extend middleware to authenticate Bearer API tokens
- Scope enforcement: middleware restricts actions per token scope
- API: CRUD endpoints gated behind Team Pro + admin
- UI: ApiTokensSection in Settings Hub with create/revoke/copy flows
- Docs: new api-tokens.mdx with usage examples and screenshots