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>

codex/parsing/grobid.py

@@ -26,6 +26,7 @@ def _text(element: ET.Element | None) -> str:
 def extract_references(
     pdf_path: str,
     grobid_url: str | None = None,
+    timeout: float = 60.0,
 ) -> list[dict[str, str]]:
     """Extract a structured reference list from a PDF via GROBID.
 
@@ -35,6 +36,9 @@ def extract_references(
         Path to the PDF file on disk.
     grobid_url:
         Base URL of the GROBID server.  Defaults to ``Settings().grobid_url``.
+    timeout:
+        HTTP client timeout in seconds.  Large PDFs (e.g. theses) can exceed the
+        60s default, especially against a slower/emulated GROBID; raise it then.
 
     Returns
     -------
@@ -46,7 +50,7 @@ def extract_references(
     if grobid_url is None:
         grobid_url = Settings().grobid_url
 
-    with open(pdf_path, "rb") as fh, httpx.Client(timeout=60.0) as client:
+    with open(pdf_path, "rb") as fh, httpx.Client(timeout=timeout) as client:
         response = client.post(
             f"{grobid_url}/api/processReferences",
             files={"input": (pdf_path, fh, "application/pdf")},