StemJSON v1.0.1

Editorial clarifications and one new appendix. No breaking changes; modules targeting 1.0 are unaffected.

• Clarified state propagation (a state action's write does not propagate through an action chain) and cross-module context inheritance.
• Clarified expression and date-casting rules; tightened the closed color list; added anti-pattern callouts.
• Documented the photos.read return contract (always an array) and the map position/region shape.
• Added Appendix C - common iOS/SwiftUI assumptions that do not hold in StemJSON.

Full normative spec: spec/v1.0.md