feat(learning-harness): absence rows travel with their registration

Eight of the ten vendored access-control rows had no named handler at all,
so every one of them would have scored `missing_context` forever rather
than as a detector miss. After the re-harvest nine are named and the tenth
states its reason.

The handler-context mode now carries the class its framework registers,
multi-line decorators, and commented-out guards -- `#@token_required`
above a ThreatByte handler is the entire bug. Where the registration lives
in another document (connexion's `operationId`, an express router), a
recipe names `context = [...]`, the harvester writes that stanza per side,
and the pair materializes both files at their repository-relative paths so
the entry-point mapper sees the layout the project has. `harvest_recipe`
fetches every blob before the first write and the driver takes `--report`,
so a failed fetch leaves a reviewed excerpt exactly as it was.

Two defects the re-harvest exposed: `.mjs` was not a known suffix, so the
one pair vendored as an ES module had no file target at all; and
`_python_route_access` matched auth words inside decorator prose, reading
`@ns.doc(description='... without proper authorization checks')` as a
guard. Recorded in the hygiene artifact: nine of the ten duplicate groups
sit on both sides of the split, which the repository-level split cannot
see.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01T7XD7x5KonMdmGRkp63EQG

tests/test_learning_classifier_report.py

@@ -44,7 +44,11 @@ def test_the_report_covers_the_whole_corpus_and_names_the_unknowns(tmp_path: Pat
     assert report.unknown == 2 and report.per_tier["static"] == len(cases) - 2  # tier one places all but two rows
     payload = report.to_dict()
     json.dumps(payload)
-    assert payload["labeled"] == 0  # no maintainer family labels in the corpus yet, and the report says so
+    # Task 4.1 declared `family` on the ten absence rows; only the four at a reference tier (`seeded`) count as labels
+    # a maintainer stands behind, and the six `title`-tier agent rows do not. Agreement over four rows of one family is
+    # not yet a measurement of the classifier, so the number is recorded, not celebrated.
+    assert payload["labeled"] == 4 and payload["agreement"] == 1.0
+    assert set(report.confusion) == {"access_control"}
 
 
 def test_agreement_uses_the_first_answer_and_the_oracle_uses_any_of_them(tmp_path: Path) -> None: