feat: update project structure and docs

app/core/__init__.py

@@ -0,0 +1 @@
+"""Core module - shared functionality and configuration."""

app/core/config.py

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+"""Application configuration and settings."""
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    """Application settings from environment variables."""
+
+    app_name: str = "Blog API"
+    debug: bool = False
+    host: str = "0.0.0.0"
+    port: int = 8000
+
+    # Database (when added)
+    database_url: str | None = None
+
+    model_config = SettingsConfigDict(env_file=".env")
+
+
+settings = Settings()

app/core/exceptions.py

@@ -0,0 +1,64 @@
+"""Custom application exceptions."""
+
+
+class AppException(Exception):
+    """Base application exception."""
+
+    def __init__(self, message: str, status_code: int = 500):
+        """Initialize application exception.
+
+        Args:
+            message: Error message.
+            status_code: HTTP status code.
+        """
+        self.message = message
+        self.status_code = status_code
+        super().__init__(self.message)
+
+
+class NotFoundError(AppException):
+    """Resource not found error."""
+
+    def __init__(self, message: str = "Resource not found"):
+        """Initialize not found error.
+
+        Args:
+            message: Error message.
+        """
+        super().__init__(message, status_code=404)
+
+
+class ValidationError(AppException):
+    """Validation error."""
+
+    def __init__(self, message: str = "Validation failed"):
+        """Initialize validation error.
+
+        Args:
+            message: Error message.
+        """
+        super().__init__(message, status_code=400)
+
+
+class UnauthorizedError(AppException):
+    """Authentication required."""
+
+    def __init__(self, message: str = "Unauthorized"):
+        """Initialize unauthorized error.
+
+        Args:
+            message: Error message.
+        """
+        super().__init__(message, status_code=401)
+
+
+class ForbiddenError(AppException):
+    """Permission denied."""
+
+    def __init__(self, message: str = "Forbidden"):
+        """Initialize forbidden error.
+
+        Args:
+            message: Error message.
+        """
+        super().__init__(message, status_code=403)