Enable pydocstyle (D) ruff rule and add more docs (#21)

* Use pydocstyle (D) rule with google convention

Add a ruff rule to catch missing documentation. Using google convention so that undocumented-param (D417) rule is enabled to catch missing params, xref https://docs.astral.sh/ruff/rules/undocumented-param. Extended to include D213 (instead of D212) and D410 rules too.

* Fix D100 Missing docstring in public module

* Fix D101 Missing docstring in public class

* Fix D103 Missing docstring in public function

Also ignore rule D205 to allow first sentence of docstring to wrap to multiple lines.

* Fix  D417 Missing argument description in the docstring

* Update indent in pyproject.toml file

tests/tools/test_buffer.py

@@ -1,3 +1,5 @@
+"""Tests for buffer tool."""
+
 from geojson_pydantic import Feature, Point
 from langchain_core.tools.base import ToolCall
 from pytest import fixture
@@ -8,6 +10,7 @@ from geo_assistant.tools.buffer import get_search_area
 
 @fixture
 def geo_assistant_fixture():
+    """Fixture with a GeoJSON point feature in a GeoAssistantState."""
     place_geojson = Feature(
         type="Feature",
         geometry=Point(type="Point", coordinates=[-9.1393, 38.7223]),
@@ -22,6 +25,7 @@ def geo_assistant_fixture():
 
 
 async def test_get_search_area(geo_assistant_fixture):
+    """Ensure that `get_search_area` tool returns a buffer Polygon."""
     # Call the underlying function directly to test the logic
     # This bypasses the injection framework which is better suited for integration tests
     command = await get_search_area.ainvoke(