Phase1 skeleton: replace demo main.py with src.server contract

- Overlay ModelHub XC Phase1 (health/status, STRATEGY_ID gate, dry-run)
- Dockerfile CMD -> python -m src.server; FROM stays platform TCR base
- Remove demo main.py and requirements.txt (stdlib only)
- Add tests/, scripts/, docs/, Makefile, config/examples (no secrets)

Makefile

@@ -0,0 +1,32 @@
+# ModelHub XC agent contrib — Phase1
+# Allowed: test / build / smoke-health / dry-run
+# FORBIDDEN: register / submit / deploy / push targets
+
+.PHONY: test build smoke-health dry-run help
+
+PYTHON ?= python3
+IMAGE  ?= modelhub-agent-contrib:local
+PORT   ?= 8080
+
+help:
+	@echo "test         stdlib unit tests + local SIGTERM integration (needs sockets)"
+	@echo "build        Docker build using platform base (needs Docker + TCR access)"
+	@echo "smoke-health local HTTP smoke (needs sockets; default test STRATEGY_ID)"
+	@echo "dry-run      local example report; pending-submit integration outstanding"
+	@echo "No register/submit/deploy/push — Phase1 hard boundary."
+
+test:
+	$(PYTHON) -m unittest discover -s tests -v
+
+build:
+	@command -v docker >/dev/null 2>&1 || { \
+	  echo "ERROR: docker not found. See docs/build-notes.md"; \
+	  exit 1; \
+	}
+	docker build -t $(IMAGE) .
+
+smoke-health:
+	$(PYTHON) scripts/smoke_health.py
+
+dry-run:
+	$(PYTHON) scripts/dry_run.py