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)

.gitignore

@@ -0,0 +1,31 @@
+# Secrets / local env
+.env
+.env.*
+!.env.example
+config/local.env
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+.venv/
+venv/
+.pytest_cache/
+.mypy_cache/
+*.egg-info/
+dist/
+build/
+
+# Dry-run / local artifacts (keep directory)
+reports/*
+!reports/.gitkeep
+
+# Editor / OS
+.DS_Store
+.idea/
+.vscode/
+*.swp
+*~
+
+# Docker
+*.tar