Serve static assets with Granian and add YAML-configurable logging

Granian serves the compiled SPA assets directly in Rust: hashed js/wasm/css
under /static (the release build uses --public-url /static/) and the card
images under /assets, configured with the GRANIAN_STATIC_PATH_ROUTE/MOUNT/
DIR_TO_FILE env vars in the Dockerfile. The Python catch-all now only serves
the SPA shell (index.html) at / and for client-side routes.

Every module logs through getLogger(__name__): lifecycle and business events
at INFO, per-move and store detail at DEBUG. The built-in default writes
DEBUG to the console; LOGGING_CONFIG points at a YAML file in the
logging.config.dictConfig schema to take over the configuration. PyYAML
becomes a direct dependency.

server/tests/test_logging_config.py

@@ -0,0 +1,66 @@
+"""Tests for the logging configuration entry point."""
+from __future__ import annotations
+
+import logging
+import tempfile
+import unittest
+from pathlib import Path
+
+from tavolo.logging_config import configure_logging
+
+
+class LoggingConfigTest(unittest.TestCase):
+    def setUp(self) -> None:
+        # configure_logging mutates the global logging state; snapshot and
+        # restore it so the rest of the suite is unaffected.
+        root = logging.getLogger()
+        self._root_handlers = root.handlers[:]
+        self._root_level = root.level
+        tavolo = logging.getLogger("tavolo")
+        self._tavolo_level = tavolo.level
+
+    def tearDown(self) -> None:
+        root = logging.getLogger()
+        root.handlers = self._root_handlers
+        root.level = self._root_level
+        logging.getLogger("tavolo").level = self._tavolo_level
+
+    def test_default_config_when_unset(self) -> None:
+        configure_logging(None)
+        root = logging.getLogger()
+        self.assertEqual(logging.DEBUG, root.level)
+        self.assertTrue(
+            any(isinstance(h, logging.StreamHandler) for h in root.handlers),
+            "default config installs a console stream handler",
+        )
+
+    def test_yaml_config_is_applied(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp:
+            config = Path(tmp) / "logging.yaml"
+            config.write_text(
+                "version: 1\n"
+                "disable_existing_loggers: false\n"
+                "root:\n"
+                "  level: WARNING\n"
+                "loggers:\n"
+                "  tavolo:\n"
+                "    level: DEBUG\n"
+            )
+            configure_logging(str(config))
+        self.assertEqual(logging.DEBUG, logging.getLogger("tavolo").getEffectiveLevel())
+        self.assertEqual(logging.WARNING, logging.getLogger().getEffectiveLevel())
+
+    def test_missing_file_raises(self) -> None:
+        with self.assertRaises(RuntimeError):
+            configure_logging("/nonexistent/logging.yaml")
+
+    def test_non_mapping_yaml_raises(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp:
+            config = Path(tmp) / "logging.yaml"
+            config.write_text("- just\n- a\n- list\n")
+            with self.assertRaises(RuntimeError):
+                configure_logging(str(config))
+
+
+if __name__ == "__main__":
+    unittest.main()