Tasks

• [x] Specify GoingToCampProvider architecture, Washington State Parks scope, and remaining deployment TODOs.
• [x] Seed WashingtonStateParks (id=12) in camply.db.data.providers and add an immutable Alembic seed migration with downgrade protection.
• [x] Add migration, packaging, and synthetic GoingToCamp provider/model/CLI/VCR regression tests.
• [x] Implement camply.providers.going_to_camp Pydantic v2 models (metadata.py, api.py), shared GoingToCampProvider ABC, and WashingtonStateParksProvider variation.
• [x] Register WashingtonStateParksProvider in camply.providers.PROVIDERS and verify provider isolation and metadata CLI integration.
• [x] Validate live Washington State Parks metadata ingestion and availability scanning in an isolated temporary SQLite database and record verification evidence.
• [x] Update DESIGN_PROVIDERS.md, PLAN.md, and CHECKLIST.md, and pass all lint, type, test, packaging, and documentation quality gates.
• [x] Decode scalar enum attributes, correct PostgreSQL upgrade expectations, and disclose booking restrictions in results.