chore: documentation (#76)

* chore: update docstring example to use python code block

* docs: add documentation

* feat: add docs build + fix other workdlows

* fix: add missing return type

docs/module/dependencies.md

@@ -0,0 +1,48 @@
+# Dependencies
+
+FastAPI dependency factories for automatic model resolution from path and body parameters.
+
+## Overview
+
+The `dependencies` module provides two factory functions that create FastAPI dependencies to fetch a model instance from the database automatically — either from a path parameter or from a request body field — and inject it directly into your route handler.
+
+## `PathDependency`
+
+[`PathDependency`](../reference/dependencies.md#fastapi_toolsets.dependencies.PathDependency) resolves a model from a URL path parameter and injects it into the route handler. Raises [`NotFoundError`](../reference/exceptions.md#fastapi_toolsets.exceptions.exceptions.NotFoundError) automatically if the record does not exist.
+
+```python
+from fastapi_toolsets.dependencies import PathDependency
+
+UserDep = PathDependency(User, User.id, session_dep=get_db)
+
+@router.get("/users/{user_id}")
+async def get_user(user: User = UserDep):
+    return user
+```
+
+The parameter name is inferred from the field (`user_id` for `User.id`). You can override it:
+
+```python
+UserDep = PathDependency(User, User.id, session_dep=get_db, param_name="id")
+
+@router.get("/users/{id}")
+async def get_user(user: User = UserDep):
+    return user
+```
+
+## `BodyDependency`
+
+[`BodyDependency`](../reference/dependencies.md#fastapi_toolsets.dependencies.BodyDependency) resolves a model from a field in the request body. Useful when a body contains a foreign key and you want the full object injected:
+
+```python
+from fastapi_toolsets.dependencies import BodyDependency
+
+RoleDep = BodyDependency(Role, Role.id, session_dep=get_db, body_field="role_id")
+
+@router.post("/users")
+async def create_user(body: UserCreateSchema, role: Role = RoleDep):
+    user = User(username=body.username, role=role)
+    ...
+```
+
+[:material-api: API Reference](../reference/dependencies.md)