chore(harness): make repository agent-ready

Add concise routed context, task-aware agent roles, focused skills, and structured learning promotion.\n\nUnify local development and workspace tooling, add layered test and E2E verification, harden MCP authentication, and gate deployment behind verification and explicit production promotion.

.codex/skills/promote-learning/SKILL.md

@@ -0,0 +1,14 @@
+---
+name: promote-learning
+description: Record or promote a reproduced Sauci agent lesson into durable documentation, a skill, fixture, or executable invariant. Use after repeated or confirmed workflow failures, not for speculative observations.
+---
+
+# Promote a learning
+
+Read `docs/agents/learnings.md` and copy `.agents/learnings/TEMPLATE.md` into the
+appropriate state directory. Include reproduction and verification evidence.
+
+Prefer one executable destination. Promotion requires review, a destination,
+and a review-after date; update the record to `promoted` only after that artifact
+exists and passes `npm run learn:check`. Never turn a transient provider failure or
+untested workaround into a golden rule.