Fix multiple bugs across pandas, data_analysis, and SunHot modules

[Copilot]

Several correctness bugs across the notebook lessons and Scrapy project: broken sort logic, wrong variable printed, resource leaks, silent crash on network failure, and a disabled pipeline.

Bug Fixes

• pandas/ch2.ipynb Cell 26 — silent no-op sort: Trailing comma after sort_values([...]) turned ascending and inplace into standalone tuple expressions; the sort never executed.

  # Before (broken — ascending/inplace are ignored)
  df.sort_values(['销售毛利','销售收入']),
  ascending=[False,True],
  inplace=(True)
  
  # After
  df.sort_values(['销售毛利','销售收入'],
                 ascending=[False,True],
                 inplace=True)

• pandas/ch3.ipynb Cells 21 & 22 — KeyError on column access: Cell 20 renames columns with (万元) suffix via inplace=True; subsequent cells still referenced the original names. Updated to 销售收入(万元) etc.

• data_analysis/Ch5.ipynb Cell 98 — wrong variable printed: print(books) dumped the entire source object instead of the filtered titles result.

• data_analysis/Ch5.ipynb Cells 91, 92, 94, 100, 104 — file handle leaks: Bare open() calls never closed. Replaced with with context managers.

• data_analysis/Ch4.ipynb — uncaught network errors: load_page() propagated URLError directly; added try/except returning None. write_page() now guards against None input instead of raising AttributeError.

• SunHot/settings.py — pipeline never ran: ITEM_PIPELINES was commented out; scraped items were never processed. Enabled SunhotPipeline.

Original prompt

分析我的项目并进一步改进，修正我项目中的错误，进一步提升预测准确性与正确率

创建自 VS Code。

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