migrate to uv + pyproject.toml

- root pyproject.toml replaces requirements.txt and requirements-worker.txt
  (worker = root + ffmpeg-python which root already had); test deps moved
  to [dependency-groups] dev
- core/gpu/pyproject.toml replaces core/gpu/requirements.txt; uses
  [tool.uv.sources] to pin torch/torchvision and paddlepaddle-gpu to their
  CUDA index URLs, replacing the manual reinstall dance from old comments
- Dockerfiles use uv sync --frozen against uv.lock for reproducible builds;
  PATH includes /app/.venv/bin so k8s manifests' bare uvicorn/celery
  commands resolve without wrapping in uv run
- core/gpu/run.sh local mode now does uv sync + uv run python server.py;
  errors out cleanly if uv is missing

pyproject.toml

@@ -0,0 +1,42 @@
+[project]
+name = "mpr"
+version = "0.1.0"
+description = "MPR — multi-pipeline runtime (api, admin, worker)"
+requires-python = ">=3.11"
+dependencies = [
+    "Django>=4.2,<5.0",
+    "django-environ>=0.11.2",
+    "fastapi>=0.109.0",
+    "uvicorn[standard]>=0.27.0",
+    "pydantic>=2.5.0",
+    "celery[redis]>=5.3.0",
+    "redis>=5.0.0",
+    "grpcio>=1.60.0",
+    "grpcio-tools>=1.60.0",
+    "boto3>=1.34.0",
+    "requests>=2.31.0",
+    "google-cloud-run>=0.10.0",
+    "strawberry-graphql[fastapi]>=0.311.0",
+    "langfuse>=2.0.0",
+    "anthropic>=0.40.0",
+    "sqlmodel>=0.0.14",
+    "psycopg2-binary>=2.9.9",
+    "opencv-python-headless>=4.8.0",
+    "numpy>=1.24.0",
+    "Pillow>=10.0.0",
+    "imagehash>=4.3.0",
+    "ffmpeg-python>=0.2.0",
+    "langgraph>=0.0.30",
+    "rapidfuzz>=3.0.0",
+]
+
+[dependency-groups]
+dev = [
+    "pytest>=7.4.0",
+    "pytest-django>=4.7.0",
+    "pytest-asyncio>=0.23.0",
+    "httpx>=0.26.0",
+]
+
+[tool.uv]
+package = false