fix(review): address PR #16 code-review findings

#1 ingest: normalize the pinned caller id (_norm_cited_id) so a non-bare DOI caller cannot store a URL-form papers.id that defeats DQ-5 idempotency / the startswith(10.) recovery gates. #2 quality.section_label: collapse to a controlled bucket only for an EXACT canonical heading; descriptive titles ('Abstract Nonsense...') keep their real title instead of being mislabelled. #4 ra_grobid_backfill: release the read connection before the slow GROBID network loop, fresh connection for the write (no idle-in-transaction across the loop over the flaky tunnel).

#5/#10 tex: flatten_inputs strips unresolved input/include at the depth cap (no literal leak on cycles); _norm_texkey strips only a single leading ./ . #6/#7 arxiv.fetch_source: keep non-.tex members resolvable for input; pick primary on an UN-commented documentclass line. #13 is_arxiv_id: also exclude http:// and arXiv-DOI forms. Tests added/updated for each.

Left as deliberate decisions: #3 (pre-section text drop is pre-existing in extract_sections; abstract stored separately), #8 (script normalizer is intentionally self-contained, already documented), #9/#11/#12 (no current trigger / tightening the gzip heuristic would reject valid old LaTeX like documentstyle / title truncation is by design on a write-only column). ruff + mypy clean.

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

scripts/rc_tex_reingest.py

@@ -50,7 +50,13 @@ def is_arxiv_id(paper_id: str) -> bool:
     with ``10.``; OpenAlex W-ids start with ``W`` or an ``https://openalex.org/`` URL.
     """
     p = (paper_id or "").strip()
-    return bool(p) and not p.startswith("10.") and not p.startswith(("W", "https://"))
+    # Exclude DOIs (incl. the arXiv DOI 10.48550/arXiv.*), OpenAlex W-ids, and any
+    # http(s) URL form; everything else is treated as a bare arXiv id.
+    return (
+        bool(p)
+        and not p.startswith(("10.", "W"))
+        and not p.lower().startswith(("http://", "https://"))
+    )
 
 
 def _section_dist(conn: psycopg.Connection[psycopg.rows.DictRow], paper_id: str) -> dict[str, int]: