Add per-paper summary verification and cap safeguards

- Per-paper summary batches are fact-checked against abstracts (verify ->
  revise once on major issues -> re-verify), controlled by SEBRIEF_VERIFY_ENABLED
- The paper cap never drops papers already published in this week's digest
  (--force re-runs could otherwise erase them from every digest)
- SEBRIEF_MAX_PAPERS default 40 -> 60 (observed weekly volume ~47)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_summarize.py

@@ -28,7 +28,7 @@ def test_summarize_dedups_gaps():
 def test_summarize_papers_batches_and_maps_by_doi():
     papers = [make_paper(f"10.1/p{i}") for i in range(5)]
     provider = FakeProvider()
-    summaries, notes = summarize_papers(papers, provider, batch_size=2)
+    summaries, notes = summarize_papers(papers, provider, batch_size=2, verify=False)
     assert notes == []
     assert set(summaries) == {p.doi for p in papers}
     assert provider.calls == ["summarize_papers:2", "summarize_papers:2", "summarize_papers:1"]
@@ -40,7 +40,7 @@ def test_summarize_papers_skips_already_summarized_and_abstractless():
     no_abstract = make_paper("10.1/empty", abstract="  ")
     todo = make_paper("10.1/todo")
     provider = FakeProvider()
-    summaries, _ = summarize_papers([done, no_abstract, todo], provider, batch_size=8)
+    summaries, _ = summarize_papers([done, no_abstract, todo], provider, batch_size=8, verify=False)
     assert set(summaries) == {"10.1/todo"}
     assert provider.calls == ["summarize_papers:1"]
 
@@ -53,7 +53,7 @@ def test_summarize_papers_failed_batch_is_noted_and_others_survive():
             return super().summarize_papers(papers)
 
     papers = [make_paper(f"10.1/p{i}") for i in range(4)]
-    summaries, notes = summarize_papers(papers, FlakyProvider(), batch_size=2)
+    summaries, notes = summarize_papers(papers, FlakyProvider(), batch_size=2, verify=False)
     assert set(summaries) == {"10.1/p2", "10.1/p3"}
     assert len(notes) == 1 and "batch 1/2" in notes[0] and "재시도" in notes[0]
 
@@ -65,10 +65,57 @@ def test_summarize_papers_discards_unknown_dois():
             items.append(PaperSummaryItem(doi="10.9/invented", **make_summary().model_dump()))
             return items, model
 
-    summaries, notes = summarize_papers([make_paper("10.1/a")], InventingProvider(), batch_size=8)
+    summaries, notes = summarize_papers([make_paper("10.1/a")], InventingProvider(), batch_size=8, verify=False)
     assert set(summaries) == {"10.1/a"} and notes == []
 
 
+def test_paper_batch_verified_ok_keeps_originals():
+    provider = FakeProvider()
+    summaries, notes = summarize_papers([make_paper("10.1/a")], provider, batch_size=8)
+    assert set(summaries) == {"10.1/a"} and notes == []
+    assert provider.calls == ["summarize_papers:1", "verify_papers"]
+
+
+def test_paper_batch_major_issue_revises_once_and_recheck():
+    major = Verification(ok=False, issues=[VerificationIssue(claim="c", problem="p", severity="major")])
+    clean = Verification(ok=True, issues=[])
+    revised = [PaperSummaryItem(doi="10.1/a", **make_summary(tldr="수정된 한 줄.").model_dump())]
+    provider = FakeProvider(paper_verifications=[major, clean], revised_papers=revised)
+    summaries, notes = summarize_papers([make_paper("10.1/a")], provider, batch_size=8)
+    assert summaries["10.1/a"].tldr == "수정된 한 줄."
+    assert notes == []
+    assert provider.calls == ["summarize_papers:1", "verify_papers", "revise_papers", "verify_papers"]
+
+
+def test_paper_batch_minor_only_skips_revision():
+    minor = Verification(ok=False, issues=[VerificationIssue(claim="c", problem="p", severity="minor")])
+    provider = FakeProvider(paper_verifications=[minor])
+    summaries, _ = summarize_papers([make_paper("10.1/a")], provider, batch_size=8)
+    assert set(summaries) == {"10.1/a"}
+    assert provider.calls == ["summarize_papers:1", "verify_papers"]
+
+
+def test_paper_batch_verify_failure_keeps_unverified_batch():
+    class BrokenVerify(FakeProvider):
+        def verify_paper_summaries(self, papers, items):
+            raise LLMError("verifier down")
+
+    summaries, notes = summarize_papers([make_paper("10.1/a")], BrokenVerify(), batch_size=8)
+    assert set(summaries) == {"10.1/a"} and notes == []
+
+
+def test_paper_batch_revise_failure_keeps_originals():
+    major = Verification(ok=False, issues=[VerificationIssue(claim="c", problem="p", severity="major")])
+
+    class BrokenRevise(FakeProvider):
+        def revise_paper_summaries(self, papers, items, issues):
+            raise LLMError("revise down")
+
+    provider = BrokenRevise(paper_verifications=[major])
+    summaries, _ = summarize_papers([make_paper("10.1/a")], provider, batch_size=8)
+    assert summaries["10.1/a"].tldr == "10.1/a 한 줄 요약입니다."
+
+
 def test_verify_ok_returns_original():
     provider = FakeProvider(verifications=[Verification(ok=True, issues=[])])
     digest = make_digest()