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/application/use_cases/update_post.py

@@ -1,4 +1,8 @@
-"""Update post use case."""
+"""Update post use case.
+
+This module implements the use case for updating blog posts.
+Supports partial updates and includes authorization checks.
+"""
 
 from uuid import UUID
 
@@ -11,13 +15,33 @@ from app.domain.value_objects import Content, Title
 
 
 class UpdatePostUseCase:
-    """Use case for updating a blog post."""
+    """Use case for updating a blog post.
+
+    Handles post updates with authorization checks.
+    Supports partial updates - only provided fields are changed.
+    Users can only update posts they authored.
+
+    Attributes:
+        _post_repo: Repository for post data access.
+        _tx_manager: Transaction manager for commit control.
+
+    Example:
+        >>> use_case = UpdatePostUseCase(post_repo, tx_manager)
+        >>> dto = UpdatePostDTO(title="New Title")
+        >>> result = await use_case.execute(post_id, dto, user_id)
+    """
 
     def __init__(
         self,
         post_repo: PostRepository,
         tx_manager: TransactionManager,
     ) -> None:
+        """Initialize use case with dependencies.
+
+        Args:
+            post_repo: Repository for post operations.
+            tx_manager: Transaction manager instance.
+        """
         self._post_repo = post_repo
         self._tx_manager = tx_manager
 
@@ -27,16 +51,27 @@ class UpdatePostUseCase:
         dto: UpdatePostDTO,
         current_user_id: str,
     ) -> PostResponseDTO:
-        """Execute the use case."""
+        """Execute the use case to update a post.
+
+        Args:
+            post_id: Unique identifier of the post to update.
+            dto: Data transfer object with update data.
+            current_user_id: ID of the user requesting update.
+
+        Returns:
+            PostResponseDTO with updated post data.
+
+        Raises:
+            NotFoundException: If post with given ID does not exist.
+            ForbiddenException: If user is not the post author.
+        """
         post = await self._post_repo.get_by_id(post_id)
         if not post:
             raise NotFoundException(f"Post with id '{post_id}' not found")
 
-        # Check authorization
         if post.author_id != current_user_id:
             raise ForbiddenException("You can only update your own posts")
 
-        # Update fields
         if dto.title is not None:
             post.update_title(Title(dto.title))
 
@@ -44,22 +79,25 @@ class UpdatePostUseCase:
             post.update_content(Content(dto.content))
 
         if dto.tags is not None:
-            # Replace all tags
             for tag in post.tags[:]:
                 post.remove_tag(tag)
             for tag in dto.tags:
                 post.add_tag(tag)
 
-        # Persist changes
         await self._post_repo.update(post)
-
-        # Commit transaction
         await self._tx_manager.commit()
 
         return self._map_to_dto(post)
 
     def _map_to_dto(self, post: Post) -> PostResponseDTO:
-        """Map domain entity to response DTO."""
+        """Map domain entity to response DTO.
+
+        Args:
+            post: Domain post entity.
+
+        Returns:
+            PostResponseDTO with all post attributes.
+        """
         return PostResponseDTO(
             id=post.id,
             title=post.title.value,