feat: update project structure and docs

app/core/config.py

@@ -0,0 +1,20 @@
+"""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()