feat: add pyproject.toml for OpenEnv multi-mode deployment

pyproject.toml

@@ -0,0 +1,25 @@
+[build-system]
+requires = ["setuptools>=68.0", "wheel"]
+build-backend = "setuptools.backends.legacy:build"
+
+[project]
+name = "customer-support-api"
+version = "1.0.0"
+description = "AI Customer Support Simulator - OpenEnv-compatible RL environment"
+requires-python = ">=3.10"
+dependencies = [
+    "fastapi>=0.100.0",
+    "uvicorn>=0.23.0",
+    "pydantic>=2.0.0",
+    "pyyaml>=6.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "httpx>=0.24.0",
+    "pytest>=7.0",
+]
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["tasks*", "graders*"]