population test: clear env for the bare-shell from_env case

from_env merges os.environ, and importing the .env-loading consumers populates
TRADING_MIN_ENTRY_GAP_PCT — so the "bare shell disables the gap gate" assertion
must delenv the key first. Test-only fix; the module behaviour is unchanged.

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

tests/unit/strategy/test_population_module.py

@@ -27,9 +27,11 @@ def test_from_env_defaults_match_production_keys():
     assert cfg.squeeze_rvol_min == 5.0
 
 
-def test_from_env_bare_shell_disables_gap_gate():
-    # No production env => min_entry_gap_pct clamps to 0.0 (gap gate off), the
-    # exact hazard the plan warns offline consumers about.
+def test_from_env_bare_shell_disables_gap_gate(monkeypatch):
+    # No production env => min_entry_gap_pct defaults to 0.0 (gap gate off), the
+    # exact hazard the plan warns offline consumers about. (from_env merges
+    # os.environ, which .env-loading imports populate — so we clear the key.)
+    monkeypatch.delenv("TRADING_MIN_ENTRY_GAP_PCT", raising=False)
     cfg = PopulationConfig.from_env(env={})
     assert cfg.min_entry_gap_pct == 0.0
     assert population_reject(cfg, gap_pct=0.05, price=10.0, volume=None, rvol=None) is None