fix: resolve ruff linting errors for CI

- Fix RUF059: prefix unused unpacked variables with underscore
  - _stat in evolution_runner.py (Mann-Whitney U test)
  - _fig in matplotlib_charts.py (plt.subplots returns)
- Fix UP038: use union syntax for isinstance (str | int | float | bool)
- Remove deprecated UP038 from ruff ignore list

All 210 tests passing, ruff checks clean.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: danielbentes

pyproject.toml

@@ -145,7 +145,6 @@ ignore = [
     "SIM108",  # ternary operators (if-else often clearer)
     "A002",    # builtin shadowing (sometimes unavoidable)
     "B007",    # unused loop variable (minor)
-    "UP038",   # isinstance style (minor)
     "C401",    # generator comprehension style (minor)
     "RUF015",  # iterator style (minor)
     "SIM118",  # dict.keys() (explicit is fine)

siare/benchmarks/corpus/index_manager.py

@@ -151,7 +151,7 @@ def create_index(
             for doc in batch:
                 doc_meta = {k: v for k, v in doc.items() if k not in ["doc_id", "text"]}
                 # Ensure all values are serializable
-                doc_meta = {k: str(v) if not isinstance(v, (str, int, float, bool)) else v
+                doc_meta = {k: str(v) if not isinstance(v, str | int | float | bool) else v
                            for k, v in doc_meta.items()}
                 # ChromaDB requires non-empty metadata or None
                 if not doc_meta:

siare/benchmarks/evolution_runner.py

@@ -657,7 +657,7 @@ def _calculate_p_value(
                 return None
 
             # Mann-Whitney U test (non-parametric)
-            stat, p_value = stats.mannwhitneyu(
+            _stat, p_value = stats.mannwhitneyu(
                 baseline, evolved, alternative="two-sided"
             )
             return float(p_value)

siare/benchmarks/visualization/matplotlib_charts.py

@@ -28,7 +28,7 @@ def radar_chart_static(
     angles = [n / float(N) * 2 * np.pi for n in range(N)]
     angles += angles[:1]  # Complete the circle
 
-    fig, ax = plt.subplots(figsize=(8, 8), subplot_kw={"polar": True})
+    _fig, ax = plt.subplots(figsize=(8, 8), subplot_kw={"polar": True})
 
     # SIARE metrics
     values = list(metrics.values())
@@ -84,7 +84,7 @@ def beir_comparison_bar_static(
     datasets = list(results.keys())
     scores = [results[d].get(metric, 0) for d in datasets]
 
-    fig, ax = plt.subplots(figsize=(12, 6))
+    _fig, ax = plt.subplots(figsize=(12, 6))
 
     bars = ax.bar(datasets, scores, color="#1f77b4", edgecolor="black")
 
@@ -130,7 +130,7 @@ def evolution_progress_static(
     gen_numbers = list(range(len(generations)))
     scores = [g.get(metric, 0) for g in generations]
 
-    fig, ax = plt.subplots(figsize=(10, 6))
+    _fig, ax = plt.subplots(figsize=(10, 6))
 
     ax.plot(gen_numbers, scores, "o-", linewidth=2, markersize=8, color="#1f77b4")