fix: total_steps now uses actual map count, not capped at 20

src/postprocessing/report_word.py

@@ -983,7 +983,7 @@ class WaterQualityReportGenerator:
             seen = set()
             tif_files = [f for f in tif_files if f.name not in seen and not seen.add(f.name)]
         n_csv = len(csv_files)
-        n_maps = min(len(tif_files), 20)
+        n_maps = len(tif_files)
         n_csv_pulses = max(1, n_csv // 10)  # 每 10 个 CSV 一次脉冲
         total_steps = 4 + n_csv_pulses + n_maps  # 固定章节 + 统计脉冲 + 每张专题图
         print(f"[公式报告] 数据: {n_csv} CSV, {len(tif_files)} 专题图 → 总步数 {total_steps}")