🚧 webdav rework

- use instance instead of class methods
- prettier cache keys

api/advent22_api/production.py

@@ -2,14 +2,14 @@ import os
 
 from granian import Granian
 from granian.constants import Interfaces, Loops
-from pydantic import BaseModel, PositiveInt
+from pydantic import BaseModel, Field
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
 class WorkersSettings(BaseModel):
-    per_core: PositiveInt = 1
-    max: PositiveInt | None = None
-    exact: PositiveInt | None = None
+    per_core: int = Field(1, ge=1)
+    max: int | None = Field(None, ge=1)
+    exact: int | None = Field(None, ge=1)
 
     @property
     def count(self) -> int: