test(rulings): the hook/route parity guards pin the rulings params (#4757)

CI 7939 went red on test_the_hook_and_the_route_agree_on_every_parameter_name:
the Bash hook now sends root and cwd, and the guard pins the exact set. Both
guards (tool-rules and prior-art) now also pin seen_ruling_systems, spelled
once in scribe_rulings_query, and check the routes read all three.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_write_path_trigger.py

@@ -970,7 +970,7 @@ def test_route_reads_every_arg_the_hook_sends():
         routes._project_scope
     )
     for arg in ("path", "code", "repo", "project_id", "exclude_ids",
-                "exclude_sync_ids", "shapes"):
+                "exclude_sync_ids", "shapes", "seen_ruling_systems"):
         assert f'request.args.get("{arg}"' in src, f"route ignores {arg}"
 
     hook = HOOK.read_text()
@@ -991,6 +991,9 @@ def test_route_reads_every_arg_the_hook_sends():
     assert "printf '&held_rule_ids=" in defs, (
         "the opened ledger's query key is no longer spelled in the helper"
     )
+    # The rulings ledger (milestone 444), shared with the tool-rules hook.
+    assert "scribe_rulings_query" in hook, "hook no longer sends the rulings ledger"
+    assert "printf '&seen_ruling_systems=" in defs
 
 
 def test_route_resolves_repo_to_a_project_not_to_a_location_filter():