Refactor configuration and enhance Telegram initData validation

- Improved formatting and readability in config.py and other files by adding line breaks.
- Introduced INIT_DATA_MAX_AGE_SECONDS to enforce replay protection for Telegram initData.
- Updated validate_init_data function to include max_age_seconds parameter for validation.
- Enhanced API to reject old initData based on the new max_age_seconds setting.
- Added tests for auth_date expiry and validation of initData in test_telegram_auth.py.
- Updated README with details on the new INIT_DATA_MAX_AGE_SECONDS configuration.

db/schemas.py

@@ -1,4 +1,5 @@
 """Pydantic schemas for API and validation."""
+
 from pydantic import BaseModel, ConfigDict
 
 
@@ -23,7 +24,7 @@ class UserInDb(UserBase):
 class DutyBase(BaseModel):
     user_id: int
     start_at: str  # ISO 8601
-    end_at: str    # ISO 8601
+    end_at: str  # ISO 8601
 
 
 class DutyCreate(DutyBase):
@@ -38,6 +39,7 @@ class DutyInDb(DutyBase):
 
 class DutyWithUser(DutyInDb):
     """Duty with full_name for calendar display."""
+
     full_name: str
 
     model_config = ConfigDict(from_attributes=True)