generate targets from S/R zones, not raw levels (consistency + strength)

Trade-setup targets now pre-merge near-duplicate S/R levels into zone
representatives (same 2% clusterer as chart + alerts) before generate_targets
runs. A clustered wall (e.g. 183 + 185) becomes one target carrying the zone's
COMBINED strength (capped 100) instead of two near-identical targets that each
undervalue the wall — which also feeds a more honest reach-probability via the
S/R-strength magnet. Representative price is the zone's near edge; the strongest
constituent's id is retained. Singleton levels pass through unchanged, so the
downstream band-spreading / probability / primary-selection pipeline and its
tests are untouched.

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

tests/unit/test_recommendation_service.py

@@ -226,3 +226,38 @@ def test_classify_by_probability_thresholds():
     assert _classify_by_probability(75) == "Conservative"
     assert _classify_by_probability(50) == "Moderate"
     assert _classify_by_probability(20) == "Aggressive"
+
+
+def test_zone_representative_levels_merges_wall():
+    """Near-duplicate resistances collapse to one zone with combined strength."""
+    from types import SimpleNamespace
+    from app.services.recommendation_service import _zone_representative_levels
+
+    levels = [
+        SimpleNamespace(id=1, price_level=183.0, type="resistance", strength=60),
+        SimpleNamespace(id=2, price_level=185.0, type="resistance", strength=60),
+        SimpleNamespace(id=3, price_level=200.0, type="resistance", strength=50),
+    ]
+    reps = _zone_representative_levels(levels, entry_price=180.0)
+
+    # 183/185 merge into one zone; 200 stays separate → 2 representatives
+    assert len(reps) == 2
+    wall = min(reps, key=lambda r: r.price_level)
+    assert wall.price_level == 183.0          # near edge of the wall
+    assert wall.strength == 100               # 60 + 60, capped at 100
+    far = max(reps, key=lambda r: r.price_level)
+    assert far.price_level == 200.0
+    assert far.strength == 50
+
+
+def test_zone_representative_levels_singletons_unchanged():
+    from types import SimpleNamespace
+    from app.services.recommendation_service import _zone_representative_levels
+
+    levels = [
+        SimpleNamespace(id=1, price_level=120.0, type="resistance", strength=70),
+        SimpleNamespace(id=2, price_level=150.0, type="resistance", strength=40),
+    ]
+    reps = _zone_representative_levels(levels, entry_price=100.0)
+    assert len(reps) == 2
+    assert {round(r.price_level) for r in reps} == {120, 150}