Mark the oracle routing test deselectable (-m 'not oracle')

The JAR route makes the test ~50s; tag it so quick iteration can skip it while
it still runs by default for validation.

tests/test_oracle.py

@@ -9,6 +9,8 @@ from __future__ import annotations
 
 from pathlib import Path
 
+import pytest
+
 from oracle import HAS_ORACLE, requires_oracle, route_dsn, routed_net_set, routed_nets
 
 FIXTURES = Path(__file__).parent / "dsn" / "fixtures"
@@ -21,6 +23,7 @@ def test_oracle_harness_imports():
     assert isinstance(HAS_ORACLE, bool)
 
 
+@pytest.mark.oracle
 @requires_oracle
 def test_oracle_routes_and_reports_connectivity():
     """Reference FreeRouting routes a routable KiCad board and we can read it back.