Rename the app from scopa to tavolo

The platform now hosts multiple card games, with scopone scientifico as
the first one. Rename the brand wherever it is not a game rule:

- move the Python package to server/src/tavolo and update imports
- rename the Postgres database/user, OIDC issuer path, client id and
  Redis key prefixes to tavolo (clean break: existing pgdata volumes and
  live games are not migrated)
- rename the Cargo package to tavolo-web and set the page title to Tavolo
- update docs and the Docker image path to woggioni/tavolo

The scopa game term (clearing the table) in the engine, state and web UI
is intentionally left untouched.

server/tests/helpers/oidc.py

@@ -1,7 +1,7 @@
 """Helpers for faking the OIDC authenticated user during tests.
 
 HTTP handlers funnel through ``oidc_mixin.get_user``; websocket handlers
-through :func:`scopa.auth.get_ws_user`. Patching those two entry points
+through :func:`tavolo.auth.get_ws_user`. Patching those two entry points
 lets route and websocket tests run entirely in-process with no IdP.
 """
 from __future__ import annotations
@@ -13,10 +13,10 @@ from typing import Iterator, Optional, Sequence
 from kaya.oidc import OIDCUser
 
 # Import the app first: it pulls in the route modules, which import
-# ``scopa.auth`` themselves. Importing ``auth`` before ``app`` would hit a
+# ``tavolo.auth`` themselves. Importing ``auth`` before ``app`` would hit a
 # partially initialized module (same constraint as reimpasto).
-from scopa.app import oidc_mixin
-from scopa import auth
+from tavolo.app import oidc_mixin
+from tavolo import auth
 
 
 def make_user(sub: str, name: Optional[str] = None) -> OIDCUser: