Add Grant Scoped Mcp Device Authorization

1. Spec And Research Grounding

• 1.1 Keep docs/research/mcp-oauth-headless-auth-prior-art-2026-06-12.md in the durable research corpus with URLs, access date, and conclusion.
• 1.2 Validate add-grant-scoped-mcp-device-authorization with openspec validate add-grant-scoped-mcp-device-authorization --strict.
• 1.3 Re-run openspec validate --all --strict before owner gate.

2. Metadata Honesty

• 2.1 Add AS metadata tests proving device authorization advertisement is token-kind honest and does not imply owner-agent device codes are normal MCP setup.
• 2.2 Update protected-resource metadata so owner-agent onboarding and grant-scoped MCP setup remain visibly distinct.
• 2.3 Update docs/skills to say headless MCP device authorization issues grant-scoped client tokens; owner-agent device authorization issues owner tokens and /mcp rejects them.

3. Grant-Scoped MCP Device Authorization

• 3.1 Add a persisted device authorization request kind for owner-agent versus grant-scoped MCP requests.
• 3.2 Implement MCP device authorization initiation for client_id, MCP resource, and PDPP authorization_details, reusing the existing client registration and pending-consent validation machinery.
• 3.3 Implement token polling so approved MCP device requests return pdpp_token_kind=client access tokens bound to the approved grant/package and resource.
• 3.4 Preserve RFC 8628 error behavior: authorization_pending, slow_down, access_denied, expired_token, invalid_grant, and invalid_client.
• 3.5 Preserve owner-agent device authorization and prove owner tokens still fail against /mcp.

4. Client And Setup UX

• 4.1 Update CLI/adapter setup guidance to show verification URL, user code, expiry, polling state, denial/expiry errors, and retry command for headless MCP setup.
• 4.2 Add bounded timeout behavior to repo-owned setup clients that poll device authorization.
• 4.3 Update hosted MCP setup docs and console connect guidance to recommend authorization-code + PKCE for browser-capable clients and grant-scoped device authorization for headless clients.

5. Verification

• 5.1 Add unit tests for owner-device and MCP-device token-kind separation.
• 5.2 Add integration smoke: device request → owner approval → token polling → /mcp tools/list succeeds with a client token.
• 5.3 Add negative smoke: owner-agent device token → /mcp rejects with the existing owner-token error.
• 5.4 Run focused AS/MCP/CLI tests.
• 5.5 Deploy only under the live-stack mutex and verify the live AS metadata, protected-resource metadata, device-flow smoke, and owner-token rejection.