docs: add AI code generation requirements and comprehensive Google-style docstrings

- Add AI code generation requirements to AGENTS.md
- Add module-level docstrings to all 46 Python modules
- Add detailed Google-style docstrings to all classes and functions
- Remove all inline comments following self-documenting code principle
- Include Args, Returns, Raises sections in function docstrings
- Add Attributes and Examples sections to class docstrings

app/domain/value_objects/title.py

@@ -1,4 +1,8 @@
-"""Title value object."""
+"""Title value object.
+
+This module defines the Title value object for blog post titles
+with validation for minimum and maximum length constraints.
+"""
 
 from dataclasses import dataclass
 
@@ -7,12 +11,35 @@ from app.domain.value_objects.base import ValueObject
 
 @dataclass(frozen=True, slots=True)
 class Title(ValueObject[str]):
-    """Blog post title value object."""
+    """Blog post title value object.
+
+    Wraps and validates blog post titles ensuring they meet length
+    requirements and are not empty.
+
+    Attributes:
+        value: The title string value.
+        MIN_LENGTH: Minimum allowed title length (3 characters).
+        MAX_LENGTH: Maximum allowed title length (200 characters).
+
+    Raises:
+        ValueError: If title is empty, too short, or too long.
+
+    Example:
+        >>> title = Title("My Blog Post")
+        >>> print(title.value)
+    """
 
     MIN_LENGTH: int = 3
     MAX_LENGTH: int = 200
 
     def _validate(self) -> None:
+        """Validate title string.
+
+        Checks that title is a non-empty string within length bounds.
+
+        Raises:
+            ValueError: If title fails validation criteria.
+        """
         if not isinstance(self.value, str):
             raise ValueError("Title must be a string")
         if len(self.value) < self.MIN_LENGTH: