refactor: rename loader/model packages to loaders/models

- Rename docforge.loader → docforge.loaders and docforge.model → docforge.models
- Update all imports, type stubs, CLI, tests, and documentation references
- Align MkDocs navigation and docforge.nav.yml with new package structure
- Adjust module docstrings and comments for consistency with pluralized naming

docforge/models/object.py

@@ -0,0 +1,76 @@
+"""
+This module defines the DocObject class, the fundamental recursive unit of the
+doc-forge documentation models. A DocObject represents a single Python entity
+(class, function, method, or attribute) and its nested members.
+"""
+
+from typing import Dict, Iterable, Optional
+
+
+class DocObject:
+    """
+    Represents a documented Python object (class, function, method, etc.).
+
+    Attributes:
+        name: Local name of the object.
+        kind: Type of object (e.g., 'class', 'function', 'attribute').
+        path: Full dotted import path to the object.
+        signature: Callable signature, if applicable.
+        docstring: Raw docstring content extracted from the source.
+        members: Dictionary mapping member names to their DocObject representations.
+    """
+
+    def __init__(
+        self,
+        name: str,
+        kind: str,
+        path: str,
+        signature: Optional[str] = None,
+        docstring: Optional[str] = None,
+    ) -> None:
+        """
+        Initialize a new DocObject.
+
+        Args:
+            name: The local name of the object.
+            kind: The kind of object (e.g., 'class', 'function').
+            path: The full dotted path to the object.
+            signature: The object's signature (for callable objects).
+            docstring: The object's docstring, if any.
+        """
+        self.name = name
+        self.kind = kind
+        self.path = path
+        self.signature = signature
+        self.docstring = docstring
+        self.members: Dict[str, 'DocObject'] = {}
+
+    def add_member(self, obj: 'DocObject') -> None:
+        """
+        Add a child member to this object (e.g., a method to a class).
+
+        Args:
+            obj: The child DocObject to add.
+        """
+        self.members[obj.name] = obj
+
+    def get_member(self, name: str) -> 'DocObject':
+        """
+        Retrieve a child member by name.
+
+        Args:
+            name: The name of the member.
+
+        Returns:
+            The requested DocObject.
+        """
+        return self.members[name]
+
+    def get_all_members(self) -> Iterable['DocObject']:
+        """
+        Get all members of this object.
+
+        Returns:
+            An iterable of child DocObject instances.
+        """
+        return self.members.values()