Implemented directory management and improved TravelDiary and Photo handling logic.

- Added `DirectoryManager` utility for consistent directory operations.
- Introduced directory name sanitization and uniqueness enforcement for `TravelDiary`.
- Updated `TravelDiaryService` with enhanced creation, update, and deletion workflows, including filesystem management.
- Improved `PhotoService` to hash files, copy photos to specific diary directories, and manage updates safely.
- Refined error handling and cascaded changes across related entities (e.g., `Entry` relationships).

src/pilgrim/utils/__init__.py

@@ -0,0 +1,3 @@
+from .directory_manager import DirectoryManager
+
+__all__ = ['DirectoryManager']

src/pilgrim/utils/directory_manager.py

@@ -0,0 +1,39 @@
+import os
+from pathlib import Path
+
+
+class DirectoryManager:
+    @staticmethod
+    def get_config_directory() -> Path:
+        """
+        Get the ~/.pilgrim directory path.
+        Creates it if it doesn't exist.
+        """
+        home = Path.home()
+        config_dir = home / ".pilgrim"
+        config_dir.mkdir(exist_ok=True)
+        os.chmod(config_dir, 0o700)
+        return config_dir
+
+    @staticmethod
+    def get_diaries_root() -> Path:
+        """Returns the path to the diaries directory."""
+        diaries_dir = DirectoryManager.get_config_directory() / "diaries"
+        diaries_dir.mkdir(exist_ok=True)
+        os.chmod(diaries_dir, 0o700)
+        return diaries_dir
+
+    @staticmethod
+    def get_diary_directory(directory_name: str) -> Path:
+        """Returns the directory path for a specific diary."""
+        return DirectoryManager.get_diaries_root() / directory_name
+
+    @staticmethod
+    def get_diary_data_directory(directory_name: str) -> Path:
+        """Returns the data directory path for a specific diary."""
+        return DirectoryManager.get_diary_directory(directory_name) / "data"
+
+    @staticmethod
+    def get_diary_images_directory(directory_name: str) -> Path:
+        """Returns the images directory path for a specific diary."""
+        return DirectoryManager.get_diary_data_directory(directory_name) / "images"