refactor to use pydantic settings and WAL sqlite mode

src/shared/settings.py

@@ -0,0 +1,31 @@
+
+from pydantic_settings import BaseSettings
+from pydantic import ConfigDict
+from typing import Annotated, Set
+from annotated_types import Len
+
+
+class Settings(BaseSettings):
+    model_config = ConfigDict(extra='ignore', str_strip_whitespace=True)
+    
+	# general
+    SERVE_LOCAL_ARCHIVE: str = ""
+    USER_GROUPS_FILENAME: str = "user-groups.yaml"
+    
+	# database
+    DATABASE_PATH: str
+    DATABASE_QUERY_LIMIT: int = 100
+    # redis
+    CELERY_BROKER_URL: str = "redis://localhost:6379"
+    CELERY_RESULT_BACKEND: str = "redis://localhost:6379"
+    REDIS_EXCEPTIONS_CHANNEL: str = "exceptions-channel"
+    
+	# observability
+    REPEAT_COUNT_METRICS_SECONDS: int = 15
+
+	# security
+    API_BEARER_TOKEN: Annotated[str, Len(min_length=20)]
+    ALLOWED_ORIGINS: Annotated[set[str], Len(min_length=1)]
+    CHROME_APP_IDS: Annotated[set[Annotated[str, Len(min_length=10)]], Len(min_length=1)]
+    BLOCKED_EMAILS: Annotated[Set[str], Len(min_length=0)] = set()
+