test(mutants,assets): a mutant is judged by the suite that owns it, 45 of 45

The runner could only run one test file, which is why PM's three
survivors from `43331fc` could not be added: two are held by the gate's
row 3 and one by the soft-hyphen door's suite. A mutant now names its
suite; the catalogue goes 39 to 45.

X3 and X4 rewritten against the code as it now stands -- a mutant table
is a copy of the code it mutates, and this round moved the lines both of
them quoted. X6 is the defeated state exactly, X7 cuts the ledger off at
its source, X8 removes the cursor rule, P6/P11/P12 are PM's three.

Two survivors on the first run, both findings, both closed:
- X4 survived because every forgery arm now fails on the ledger check
  before the binding is reached. An arm was added where the run DID book
  the pair and the block stating it points at another picture.
- X5 survived the WHOLE suite -- 2134 passed with the disarming removed
  -- because a document-supplied field can no longer reach the gate. The
  property is about the BUNDLE and not about one judge, so it is kept and
  measured in `tests/test_assets.py`, with a known-positive counting the
  run's own two fields on the same expression.

killed 45 of 45, exit 0. Report, CHANGELOG and CLAUDE.md written.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_accounting_gate.py

@@ -755,13 +755,30 @@ def test_a_document_cannot_forge_a_conversion_claim(tmp_path: Path) -> None:
     # KNOWN-POSITIVE on the same bytes: the last arm's text, believed once the
     # RUN books the pair. Without it every arm above would pass on a route
     # that had simply stopped working.
+    booked = _ledger((before, after))
     honest = _build(
         assets=assets,
         bundle_text=arms["that block alone in the bundle"],
-        accounting=_ledger((before, after)),
+        accounting=booked,
     )
     assert gate.asset_holds(honest, never_carried) is True
 
+    # THE ASSET BINDING, ON ITS OWN. The run booked this pair and the block
+    # stating it points at a different picture -- a sentence nothing here
+    # writes. Measured 2026-09-19: with the ledger in front of it, every arm
+    # above passes whether or not the binding is checked, so without this the
+    # mutant that removes it survives the whole suite.
+    misplaced = _build(
+        assets=assets,
+        bundle_text=(
+            f"![Figur](/assets/{other[:12]}-annen.png)\nImage: figur.bmp (8x4 px) -- {clause}\n"
+        ),
+        accounting=booked,
+    )
+    assert gate.asset_holds(misplaced, never_carried) is False, (
+        "a clause in one asset's block spoke for another asset's digest"
+    )
+
 
 def test_the_build_never_writes_a_claim_the_document_supplied(tmp_path: Path) -> None:
     """PM's measured path, end to end through the real `okf build`.