Plans are created by importing JWT claims with @type: PlanAction via
POST /api/v2/claim, not through a dedicated plan creation endpoint.
Changes:
- Document POST /api/v2/claim route in localhost-testing-guide.md
- Add Method 6 (PlanAction JWT import) to getting-valid-plan-ids.md
- Update seed-test-projects.js with warnings about PlanAction JWT requirements
- Clarify that seed script cannot create plans (requires DID signing)
This reflects the actual TimeSafari API architecture where plans are
created as a side effect of importing PlanAction claims.