feat(grobid): R-A reference backfill + native arm64 GROBID on Jetson

Enable roadmap R-A (GROBID reference extraction) end-to-end and run it
against local Jetson infra instead of a Mac/Rosetta emulation.

Backfill:
- Add scripts/ra_grobid_backfill.py: references-only, idempotent citation
  backfill (dry-run default). Deliberately not ingest_paper(source_path=pdf),
  which re-OCRs and replaces the DQ-3-clean .txt chunks; this touches only the
  citations table (ON CONFLICT DO NOTHING). 7 tests.
- Make extract_references timeout configurable (large theses exceed the 60s
  default, especially against a slower GROBID).

Jetson infra:
- Bump grobid/grobid 0.8.2 -> 0.9.0-crf. The -crf tag is the only GROBID
  variant published as an arm64 multi-arch manifest; every 0.8.x tag and the
  full deep-learning image are amd64-only, which is why GROBID never ran on the
  aarch64 Jetson. Enable the 4g memory cap + init/ulimits per GROBID docs.
- Add docs/infra/grobid-jetson.md runbook: arm64 image rationale, the two host
  prerequisites (docker-group membership + the Compose v2 CLI plugin, both
  missing on the Jetson), service-scoped deploy, and the GET /api/isalive check.
  Verified live 2026-06-17: native arm64 pull, isalive=true, end-to-end
  extract_references on lutz-2024-thesis.pdf = 116 refs (101 with DOI/arXiv).

docs(audit): mark R-A core done (citing coverage 27/29 -> 29/29; edges 920 -> 1022).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/audit/DATA-QUALITY-2026-06-15.md

@@ -338,7 +338,33 @@ so the quality lever is *combining more free sources*, not buying paywall access
 Paywall/uni-login was explicitly considered and **deferred** (see R-E). Each item
 is self-contained so a cold session can pick it up.
 
-### R-A — Run GROBID reference extraction on arXiv PDFs · **HIGH lever, LOW-MED effort**
+### R-A — Run GROBID reference extraction on PDFs · **CORE DONE 2026-06-17** (full sweep optional)
+
+**Resolution (what was done) — citing coverage 27/29 → 29/29 (100%); edges 920 → 1022:**
+- **References-only backfill, not full re-ingest.** Added
+  [scripts/ra_grobid_backfill.py](../../scripts/ra_grobid_backfill.py): per paper,
+  run `grobid.extract_references(pdf)`, normalize cited-ids to the canonical bare
+  form (DOIs de-URL'd + lower-cased; `arXiv:` stripped), INSERT into `citations`
+  (`ON CONFLICT DO NOTHING`). Deliberately avoids `ingest_paper(source_path=pdf)`,
+  whose PDF branch re-runs Nougat + `DELETE FROM chunks` and would overwrite the
+  DQ-3-verified-clean `.txt` chunks (and needs Nougat). Idempotent; dry-run by
+  default; 7 tests; ruff/mypy clean.
+- **GROBID provisioning:** the pinned `grobid/grobid:0.8.2` is amd64-only, but the
+  Jetson and the dev Mac are both arm64 (this is why GROBID never ran). Ran the
+  lighter CRF image (`grobid/grobid:0.8.2-crf`) on the Mac under Podman+Rosetta
+  (PDFs are local; citations written over the SSH DB tunnel). Made
+  `extract_references` timeout configurable (theses need >60s emulated). A separate
+  task is provisioning a native arm64 GROBID on the Jetson (`docs/infra/grobid-jetson.md`).
+- **Both `depositonce` theses closed:** `…depositonce-20357` (lutz-2024) **+96**
+  edges (5 in-corpus); `…depositonce-5415` (sechelmann-2016) **+6** edges — its
+  147 MB/173-page scan blew pdfalto's 120s limit, so the 9 bibliography pages were
+  extracted with PyMuPDF first (77 refs, only 6 with a DOI/arXiv). **No paper has
+  zero out-edges now.**
+- **Optional remaining (secondary acceptance):** sweep the other 27 already-covered
+  papers for *extra* GROBID refs via `python scripts/ra_grobid_backfill.py --write`
+  (the 2 book PDFs need the same bib-page extraction as sechelmann).
+
+**Original plan (for context):**
 - **✓ Unblocked (DQ-5 RESOLVED 2026-06-17):** DOI re-ingest is now idempotent, so
   the GROBID re-ingest no longer aborts on `papers_openalex_id_key`.
 - **What:** the whole corpus was ingested from `.txt` (`PAPERS_DIR=…/papers/txt`),