fix: ruff findings

tests/test_projection.py

@@ -9,7 +9,6 @@ Covers acceptance criteria:
 - PR-13: Baseline provenance and validation per register
 - PR-17: Arithmetic exactly E_rated = TBW * 10^12, E_implied = 100*W/p, projected = max(E-W,0)/rate
 """
-import sqlite3
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
 
@@ -18,11 +17,10 @@ import sys
 sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
 
 from fenris.store import init_store
-from fenris.monitoring_periods import ensure_period_open, close_period
+from fenris.monitoring_periods import ensure_period_open
 from fenris.projection import (
     compute_projection, ConfidenceState, BaselineTier, ScenarioRange,
-    TBW_TO_BYTES, HORIZON_DAYS, WARMING_MIN_DAYS, STALENESS_HOURS,
-    YOUNG_REGIME_DAYS, DISCLOSURES, _compute_horizon_rate,
+    TBW_TO_BYTES, DISCLOSURES,
 )
 
 
@@ -1039,8 +1037,6 @@ class TestEvidenceAnchoredHorizons:
             # cumulative_bytes = 30 * 100 * 1024 * 1024
             # rate = cumulative_bytes / wall_clock
             # headline = (E_baseline - cumulative_bytes) / rate
-            E_baseline = 10.0 * TBW_TO_BYTES
-            cumulative_bytes = 30 * bw
             assert result.headline_remaining_seconds >= 0
 
     def test_zero_boundary_delta_returns_zero(self, store):