feat: bootstrap backend MVP and architecture docs

app/core/config.py

@@ -0,0 +1,46 @@
+from functools import lru_cache
+from typing import Annotated
+
+from pydantic import field_validator
+from pydantic_settings import BaseSettings, NoDecode, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", extra="ignore")
+
+    app_env: str = "development"
+    port: int = 8000
+
+    db_host: str = "127.0.0.1"
+    db_port: int = 54321
+    db_name: str = "member_center"
+    db_user: str = "member_ose"
+    db_password: str = ""
+
+    authentik_base_url: str = ""
+    authentik_admin_token: str = ""
+    authentik_verify_tls: bool = False
+
+    public_frontend_origins: Annotated[list[str], NoDecode] = ["https://member.ose.tw"]
+    internal_shared_secret: str = ""
+
+    @field_validator("public_frontend_origins", mode="before")
+    @classmethod
+    def parse_origins(cls, value: str | list[str]) -> list[str]:
+        if isinstance(value, list):
+            return value
+        if not value:
+            return []
+        return [origin.strip() for origin in value.split(",") if origin.strip()]
+
+    @property
+    def database_url(self) -> str:
+        return (
+            "postgresql+psycopg://"
+            f"{self.db_user}:{self.db_password}@{self.db_host}:{self.db_port}/{self.db_name}"
+        )
+
+
+@lru_cache
+def get_settings() -> Settings:
+    return Settings()