test(gates): retire the K2 track; re-measure the retrieval gate's premises for BM25

Operator decision 2026-09-21: the test track built on material tied to the
operator's employer (K2) is retired -- not re-measured, not frozen. Public
tests and gates run on invented material.

Retrieval gate:
- The four FUSION_PREMISE xfails are gone and pass through their INPUTS: the
  synthetic MISS, LOOKUP and QUOTA bundles were re-measured for BM25 (the
  miss fasit no longer shares the rare word `maa`; lookup and quota decoys
  carry the question's words so each partition and the quota decide their
  own fixture). SPECS_SHA256 moved with them. Rows 2 and 3 green again.
- Row 7's mutants M04, M06, M07, M08, M10 now patch `bm25`, the code the
  default runs. Three survive with 0 ranks moved (passage body, title
  weight, bm25.RRF_K), each with its mechanism printed. M07 was not forced:
  every synthetic body carries its title as a heading.
- Row 9 (K2) removed; row 8 requires `wiki-20` alone, the `r761` and
  `vegnormal` adapters are gone. Chose the broad reading of "K2" because the
  operator decision defines it as employer-tied material and the order's
  grep includes `vegnormal`.

Also removed: tests/test_default_bundle_pin.py, the K2 arms of
test_okf_consume, the four real-arm tests of test_quality, the R761 soft
hyphen test, the N101/N200 delivery tests and okf_accounting_gate's default
real corpus (and H5's guard, which only existed for those defaults). Two
fixtures carrying road-standard identifiers are rewritten with invented ones.

Gate after: 1 10/10, 2 7/7, 3 5/5, 4 6/6, 5 0/1, 6 10/10, 7 11/14,
8 NOT RUN -> GATE RED: rows 5, 7, 8. Suite 2423 passed, 1 skipped,
0 xfailed.

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

tests/test_frontmatter_nesting.py

@@ -37,15 +37,15 @@ from llm_ingestion_okf.structure import derive_document_structure
 # rather than only asserting that they could.
 NESTED = """\
 ---
-title: N100.2 Kryss og avkjoersler
+title: H100.2 Hytter og uthus
 generated: true
-source_file: vegnormal.md
+source_file: haandbok.md
 sources:
-  - resource: https://example.test/bruprosjektering.pdf
-    title: N200.7 Bruprosjektering
+  - resource: https://example.test/broeyting.pdf
+    title: H200.7 Broeyting
 ---
 
-# Kryss og avkjoersler
+# Hytter og uthus
 
 Body text.
 """
@@ -53,12 +53,12 @@ Body text.
 # The same document with the nested block removed. Nothing else differs.
 FLAT = """\
 ---
-title: N100.2 Kryss og avkjoersler
+title: H100.2 Hytter og uthus
 generated: true
-source_file: vegnormal.md
+source_file: haandbok.md
 ---
 
-# Kryss og avkjoersler
+# Hytter og uthus
 
 Body text.
 """
@@ -73,46 +73,46 @@ Body text.
 
 
 def test_control_materialize_reads_top_level_title(tmp_path: Path) -> None:
-    path = tmp_path / "vegnormal.md"
+    path = tmp_path / "haandbok.md"
     path.write_text(FLAT, encoding="utf-8")
-    assert parse_frontmatter(path)["title"] == "N100.2 Kryss og avkjoersler"
+    assert parse_frontmatter(path)["title"] == "H100.2 Hytter og uthus"
 
 
 def test_control_structure_reads_top_level_title() -> None:
     declared, offset = _structure_split(FLAT)
-    assert declared["title"] == "N100.2 Kryss og avkjoersler"
+    assert declared["title"] == "H100.2 Hytter og uthus"
     assert offset > 0
 
 
 def test_control_profiles_reads_top_level_title() -> None:
     head, _body = _profiles_split(FLAT)
-    assert head["title"] == "N100.2 Kryss og avkjoersler"
+    assert head["title"] == "H100.2 Hytter og uthus"
 
 
 def test_control_derivation_reads_top_level_title() -> None:
-    structure = derive_document_structure(FLAT, source_file="vegnormal.md")
-    assert structure.title == "N100.2 Kryss og avkjoersler"
-    assert structure.number == "N100.2"
-    assert structure.parent_number == "N100"
+    structure = derive_document_structure(FLAT, source_file="haandbok.md")
+    assert structure.title == "H100.2 Hytter og uthus"
+    assert structure.number == "H100.2"
+    assert structure.parent_number == "H100"
 
 
 # --- the defect, once per parser copy ------------------------------------
 
 
 def test_nested_title_does_not_substitute_in_materialize(tmp_path: Path) -> None:
-    path = tmp_path / "vegnormal.md"
+    path = tmp_path / "haandbok.md"
     path.write_text(NESTED, encoding="utf-8")
-    assert parse_frontmatter(path)["title"] == "N100.2 Kryss og avkjoersler"
+    assert parse_frontmatter(path)["title"] == "H100.2 Hytter og uthus"
 
 
 def test_nested_title_does_not_substitute_in_structure() -> None:
     declared, _offset = _structure_split(NESTED)
-    assert declared["title"] == "N100.2 Kryss og avkjoersler"
+    assert declared["title"] == "H100.2 Hytter og uthus"
 
 
 def test_nested_title_does_not_substitute_in_profiles() -> None:
     head, _body = _profiles_split(NESTED)
-    assert head["title"] == "N100.2 Kryss og avkjoersler"
+    assert head["title"] == "H100.2 Hytter og uthus"
 
 
 # --- the propagation the order asks to be MEASURED, not assumed ----------
@@ -127,10 +127,10 @@ def test_substituted_title_moves_number_and_parent() -> None:
     question was whether `number` and `parent` move in PRACTICE or only in
     theory.
     """
-    structure = derive_document_structure(NESTED, source_file="vegnormal.md")
-    assert structure.title == "N100.2 Kryss og avkjoersler"
-    assert structure.number == "N100.2"
-    assert structure.parent_number == "N100"
+    structure = derive_document_structure(NESTED, source_file="haandbok.md")
+    assert structure.title == "H100.2 Hytter og uthus"
+    assert structure.number == "H100.2"
+    assert structure.parent_number == "H100"
 
 
 def test_nested_key_does_not_invent_a_top_level_field() -> None:
@@ -141,7 +141,7 @@ def test_nested_key_does_not_invent_a_top_level_field() -> None:
     document never declared. `derive_document_structure` exposes `declared`
     directly, so this pins the namespace itself and not one lucky key.
     """
-    structure = derive_document_structure(NESTED, source_file="vegnormal.md")
+    structure = derive_document_structure(NESTED, source_file="haandbok.md")
     assert "resource" not in structure.declared
     assert set(structure.declared) == {"title", "generated", "source_file", "sources"}
 
@@ -159,7 +159,7 @@ def test_flow_form_still_round_trips(tmp_path: Path) -> None:
     """
     flow = (
         "---\n"
-        "title: N100.2 Kryss og avkjoersler\n"
+        "title: H100.2 Hytter og uthus\n"
         "generated: { by: process:okf-ingest, at: 2026-08-31T00:00:00Z }\n"
         "sources: [ a.pdf, b.pdf ]\n"
         "---\n\nBody.\n"
@@ -169,4 +169,4 @@ def test_flow_form_still_round_trips(tmp_path: Path) -> None:
     parsed = parse_frontmatter(path)
     assert parsed["generated"] == "{ by: process:okf-ingest, at: 2026-08-31T00:00:00Z }"
     assert parsed["sources"] == "[ a.pdf, b.pdf ]"
-    assert parsed["title"] == "N100.2 Kryss og avkjoersler"
+    assert parsed["title"] == "H100.2 Hytter og uthus"