MAINT: Move code from _page.py to _text_extraction

[MartinThoma]

The goal of this PR is to increase maintainabilty by reducing the size of __page.py. This helps, because:

• The risk of merge conflicts decreases
• It becomes easier to see which kind of change is done

It also prepares for a big more complex refactoring (see #3339 )

For the Reviewer

This PR is almost only copy-paste (moving the location of the code, but no additions/changes):

• The license preamble was added
• The new TextExtration class was added + used by _page.py
• _get_actual_font_widths and _handle_tj were only moved

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.73%. Comparing base (dfadde5) to head (aae5d9f).
⚠️ Report is 66 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3343   +/-   ##
=======================================
  Coverage   96.73%   96.73%           
=======================================
  Files          53       54    +1     
  Lines        9060     9069    +9     
  Branches     1676     1676           
=======================================
+ Hits         8764     8773    +9     
  Misses        177      177           
  Partials      119      119           

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[Copilot]

Pull Request Overview

This PR moves code related to PDF text extraction from _page.py to a dedicated file in _text_extraction to improve maintainability and reduce merge conflicts. Key changes include:

• Moving the implementations of _get_actual_font_widths and _handle_tj into a new TextExtraction class.
• Adding a license preamble and creating a new file (pypdf/_text_extraction/_text_extractor.py) to house the extracted methods.
• Updating _page.py to remove duplicate logic and use the new TextExtraction instance.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
pypdf/_text_extraction/_text_extractor.py	New file with the TextExtraction class and moved text extraction logic.
pypdf/_page.py	Removed duplicate extraction functions and updated calls to use the new TextExtraction class.

[stefan6419846]

Just did a quick check myself and the diff looks correct.