fix(package): review pass on the PyPI package

- docsgpt api binds 127.0.0.1 by default, like gunicorn and uvicorn do;
  --host 0.0.0.0 exposes it. The docs say so.
- The embedded Milvus and LanceDB defaults derive from the data home, so
  they follow DOCSGPT_HOME like the faiss indexes and uploads do. A checkout
  run from its root and the Docker image resolve to the same paths as before.
- The docs and the pyproject comment describe the CPU torch install as two
  steps (torch and torchvision from the PyTorch CPU index first, then the
  docling extra): pip picks the highest version across indexes, so
  --extra-index-url only yields the CPU build while that index keeps pace
  with PyPI.
- AGENTS.md separates DOCSGPT_HOME (moves the data home) from
  DOCSGPT_ENV_FILE (selects the .env file); the docs example uses a password
  placeholder.

tests/test_cli.py

@@ -43,7 +43,7 @@ class TestApi:
         run.assert_called_once_with()
         argv = sys.argv
         assert argv[0] == "gunicorn" and argv[-1] == "docsgpt.asgi:asgi_app"
-        assert argv[argv.index("--bind") + 1] == "0.0.0.0:8000"
+        assert argv[argv.index("--bind") + 1] == "127.0.0.1:8000"
         assert argv[argv.index("-w") + 1] == "2"
         assert argv[argv.index("-k") + 1] == "docsgpt.gunicorn_worker.BoundedDrainUvicornWorker"
         assert argv[argv.index("--config") + 1] == "python:docsgpt.gunicorn_conf"