Centralize paths in paths.py and harden waybill-number handling

- Add paths.py: BASE_DIR/DOWNLOAD_DIR/CONFIG_PATH anchored on __file__
  so paths resolve regardless of the launch cwd
- Route main_router and all site modules through DOWNLOAD_DIR/CONFIG_PATH,
  replacing os.getcwd()-based download dirs and the "config.yaml" literal
- main_router compare engine: read Excel as str with keep_default_na,
  strip/normalize 运单号, drop blanks, and isin against a set so
  int/float-vs-str mismatches no longer produce false "undelivered"
- Shunxin: give downloaded files unique microsecond temp names and read
  Excel as str to preserve long-waybill precision
- Normalize bare except: to except Exception: across affected files

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

paths.py

@@ -0,0 +1,15 @@
+# paths.py
+# 统一的路径锚点：所有路径都以本项目所在目录为基准，避免依赖运行时的工作目录(cwd)。
+# 这样无论从哪个目录启动脚本（IDE / 命令行 / 计划任务 / 双击），
+# 下载目录与配置文件都能稳定定位，不会出现“文件落到别处”或“读不到密码”的隐蔽故障。
+
+import os
+
+# 项目根目录（以本文件所在位置为基准，与从哪个目录启动脚本无关）
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+
+# 统一的下载 / 输出目录
+DOWNLOAD_DIR = os.path.join(BASE_DIR, "downloads")
+
+# 统一的配置文件路径（注意：config.yaml 需与本项目脚本放在同一目录下）
+CONFIG_PATH = os.path.join(BASE_DIR, "config.yaml")