feat(halacha): application gate + lexical dedup tail + quality harnesses (#81,#82)

Halacha-extraction quality (#81) and dedup-on-insert (#82) — engine changes
(pure + tested) plus measurement/ops tooling.

halacha_quality.py
- #81.4 application gate: is_fact_dependent() (high-precision "applied to THIS
  case" deixis per the strict rubric §3/§27) + FLAG_APPLICATION. compute_quality_flags
  now takes rule_type and flags rule_type=='application' OR fact-dependent —
  blocking auto-approve (an illustration is not a generalizable holding).
- #82.3 lexical tail signal: jaccard_shingles / normalized_levenshtein /
  lexical_near_duplicate + FLAG_NEAR_DUPLICATE, for the 0.83–0.93 cosine band.

halacha_extractor.py — pass rule_type to the flag computation; re-type a
binding-labeled fact-application to 'application' (mirrors non_decision→obiter).

db.py (store_halachot_for_chunk) — dedup now fetches the nearest same-precedent
neighbor once: cosine ≥ DEDUP → skip (unchanged); cosine in [BAND, DEDUP) with
high lexical overlap → FLAG_NEAR_DUPLICATE (review, not skip — never drop a
possibly-distinct principle unreviewed).

config.py — HALACHA_DEDUP_BAND_COSINE (0.83).

Scripts:
- scripts/halacha_goldset.py (#81.7) — export stratified sample for human
  tagging; score validators (P/R/F1) against the tags. Backbone for #81.8.
- scripts/halacha_batch_reconcile.py (#82.7) — conservative cross-precedent
  dedup (cosine ≥0.95), dry-run report only.
- scripts/calibrate_halacha_dedup.py (#82.1) — calibrate the lexical thresholds
  against the 2026-06-03 cleanup gold-set.

Deferred (documented): #82.4 merge-provenance and #82.5 DB ON CONFLICT/UNIQUE
on normalized quote are NOT included — the current skip+flag behavior is safe,
whereas a UNIQUE on normalized_quote would fail on existing dups and a blind
merge risks losing provenance; they need their own chair-reviewed migration.
#82.6 over-merge guard is moot until merge lands. #81.6 full rhetorical-role
classifier deferred (section pre-filter + application flag cover the practical
case); #81.8 blocked on the human-tagged gold-set (harness now provided).

Verified:
- pytest tests/test_halacha_quality.py — 52 passed (14 new).
- calibrate: configured (0.55,0.70) → precision 1.0 (zero false-merge), recall
  0.30 — correct profile for an auto-approve-blocking signal.
- goldset export: 15-row sample CSV. batch reconcile: 819 halachot → 5
  cross-precedent candidate pairs.

Invariants: G1 (normalize at source — flag at insert, not at read); §6 (no
silent swallow — suspect items flagged to review, never dropped); G2 (no
parallel path — same store_halachot_for_chunk / compute_quality_flags).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mcp-server/tests/test_halacha_quality.py

@@ -181,3 +181,75 @@ def test_consolidation_priority_prefers_approved_then_confidence():
                   "quote_verified": True, "rule_statement": "x"}
     # approved sorts before higher-confidence pending → kept as canonical
     assert min([approved, pending_hi], key=he._consolidation_priority)["id"] == "a"
+
+
+# ── #81.4 fact-dependent / application ──
+
+@pytest.mark.parametrize("rule", [
+    "במקרה דנן ועדת הערר קבעה כי ההיתר בטל",
+    "בענייננו אין הצדקה לפיצוי",
+    "בערר שלפנינו הוכח כי השומה שגויה",
+])
+def test_is_fact_dependent_hits(rule):
+    assert hq.is_fact_dependent(rule) is True
+
+
+@pytest.mark.parametrize("rule", [
+    "ועדת הערר מוסמכת לדון בהיטל השבחה",
+    "נטל ההוכחה מוטל על המבקש",
+    "פגיעה תכנונית מזכה בפיצוי לפי סעיף 197",
+])
+def test_is_fact_dependent_misses(rule):
+    assert hq.is_fact_dependent(rule) is False
+
+
+def test_application_flag_from_rule_type():
+    flags = hq.compute_quality_flags(
+        "נטל ההוכחה על המבקש", "נטל ההוכחה על המבקש כאמור",
+        rule_type="application",
+    )
+    assert hq.FLAG_APPLICATION in flags
+
+
+def test_application_flag_from_deixis_even_if_binding():
+    flags = hq.compute_quality_flags(
+        "במקרה דנן נדחה הערר", "כפי שקבענו במקרה דנן נדחה הערר",
+        rule_type="binding",
+    )
+    assert hq.FLAG_APPLICATION in flags
+
+
+def test_clean_binding_rule_has_no_flags():
+    flags = hq.compute_quality_flags(
+        "ועדת הערר מוסמכת לדון בטענות חוקתיות הנוגעות לתכנית",
+        "הוועדה מוסמכת לדון אף בטענות מסוג זה, ככל שהן נוגעות לתכנית שבנדון.",
+        rule_type="binding",
+    )
+    assert flags == []
+
+
+# ── #82.3 lexical near-duplicate signal ──
+
+def test_jaccard_high_for_reworded_same_rule():
+    a = "נטל ההוכחה בהיטל השבחה מוטל על הוועדה המקומית"
+    b = "נטל ההוכחה בהיטל השבחה מוטל על הוועדה המקומית בלבד"
+    assert hq.jaccard_shingles(a, b) >= 0.5
+
+
+def test_jaccard_low_for_distinct_rules():
+    a = "ועדת הערר מוסמכת לדון בהיטל השבחה"
+    b = "המועד להגשת ערר הוא שלושים יום"
+    assert hq.jaccard_shingles(a, b) < 0.2
+
+
+def test_normalized_levenshtein_identical_and_disjoint():
+    assert hq.normalized_levenshtein("אבג", "אבג") == 1.0
+    assert hq.normalized_levenshtein("", "אבג") == 0.0
+
+
+def test_lexical_near_duplicate_band():
+    a = "נטל ההוכחה בהיטל השבחה מוטל על הוועדה המקומית"
+    b = "נטל ההוכחה בהיטל השבחה מוטל על הוועדה המקומית, כך נפסק"
+    assert hq.lexical_near_duplicate(a, b) is True
+    c = "המועד להגשת ערר על שומה הוא שלושים ימים"
+    assert hq.lexical_near_duplicate(a, c) is False