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

benchmarks/pairs/agent-vfc/openniw-jobs-0fc947/fixed.py

@@ -1,4 +1,4 @@
-# Provenance: HHHHHejia/openniw  (fixed).
+# Provenance: HHHHHejia/openniw get_job (fixed).
 # repo: HHHHHejia/openniw
 # commit: 0fc94733f6ca3c6b129a0a8e6d7b3acce19d5a10
 # parent: 4d91ed82fa9a5ec6bf5ef96da1d221fc187700dc
@@ -9,7 +9,9 @@
 # relpath: backend/app/routers/jobs.py
 # provenance: agent
 # mechanism: identity_from_request_body
+# upstream_start: 9
 
+@router.get("/{job_id}")
 async def get_job(job_id: str, user: dict = Depends(auth.current_user)) -> dict:
     job = await jobs_service.get(job_id)
     if job is None:

benchmarks/pairs/agent-vfc/openniw-jobs-0fc947/vuln.py

@@ -1,4 +1,4 @@
-# Provenance: HHHHHejia/openniw  (vuln).
+# Provenance: HHHHHejia/openniw get_job (vuln).
 # repo: HHHHHejia/openniw
 # commit: 4d91ed82fa9a5ec6bf5ef96da1d221fc187700dc
 # parent: 4d91ed82fa9a5ec6bf5ef96da1d221fc187700dc
@@ -9,7 +9,9 @@
 # relpath: backend/app/routers/jobs.py
 # provenance: agent
 # mechanism: identity_from_request_body
+# upstream_start: 9
 
+@router.get("/{job_id}")
 async def get_job(job_id: str, user: dict = Depends(auth.current_user)) -> dict:
     job = await jobs_service.get(job_id)
     if job is None: