Harden the portable skill runtime for agent-native discovery and release

[CountableNewt]

Goal

Turn the #19 portable runtime into a small, standards-aligned agent API and release it through Development before an explicitly approved Production promotion.

Deliverables

• Preserve and publish the pending Railway cutover changes without absorbing unrelated work.
• Upgrade the MCP contract foundation for typed JSON schemas/results and correct protocol errors.
• Default to three tools: resolve_context, get_skill, and report_skill_feedback.
• Retain hidden one-release compatibility aliases.
• Support standard Agent Skills packages plus .mycontext/skills.yaml routing policy.
• Enforce scope, activation, conflicts, capabilities, fallbacks, and deterministic ordering.
• Remove unused embedding controls.
• Add transactional administration and package-file storage.
• Verify with Codex and Claude in Development, then complete a one-hour soak.
• Promote to Production only after Configure Railway production tokens for tenant domains and CI deploys #23 and explicit approval.

Release gates

1. Full local CI and migration matrix.
2. Exact-SHA Railway Development deployment, Gateway before Web.
3. Authenticated Codex and Claude proof plus one-hour soak.
4. Configure Railway production tokens for tenant domains and CI deploys #23 complete.
5. Explicit Production approval.
6. Exact-SHA Production deployment and one-hour observation.

Rollback

Restore prior Railway service snapshots while leaving additive schema intact. Database restoration is reserved for confirmed corruption and separate approval.

[linear-code]

MCP-5