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>

tests/parsing/test_tex.py

@@ -146,6 +146,18 @@ class TestFlattenInputs:
         assert r"\input" not in out
         assert "A" in out and "B" in out
 
+    def test_input_cycle_does_not_leak_directive(self) -> None:
+        # a -> b -> a: the depth cap must strip the unresolved directive, not leak it.
+        files = {"a.tex": r"AA \input{b}", "b.tex": r"BB \input{a}"}
+        out = flatten_inputs(files["a.tex"], files)
+        assert r"\input" not in out
+        assert "AA" in out and "BB" in out
+
+    def test_dot_slash_prefix_resolves_without_overstrip(self) -> None:
+        # "./intro" resolves intro.tex; lstrip must not eat a real leading dot/run.
+        files = {"main.tex": r"\input{./intro}", "intro.tex": "BODY"}
+        assert "BODY" in flatten_inputs(files["main.tex"], files)
+
 
 class TestChunkSections:
     def test_pairs_carry_section_titles(self) -> None: