Add page numbering and footer to summary plots

[chris-ashe]

This pull request enhances the plot_summary function in process/core/io/plot/summary.py by adding a standardized footer to each generated plot page, improving document clarity and traceability. The footer includes run metadata and page numbering for both PDF and PNG outputs.

Plot output improvements:

• Added the add_page_footer function to append a footer on each plot page with the run label and page number/total pages, ensuring consistent annotation across all output pages.
• The run label in the footer now displays key metadata from the MFile (file prefix, scan number, date, time, tag number, and branch name), making each page self-descriptive.

Code structure and maintainability:

• Refactored the code to use a single MFile object (mfile_obj) for metadata extraction and to construct the run label, reducing redundant object creation.
• Updated both PDF and PNG export loops to call add_page_footer before saving, ensuring the footer is present in all output formats.

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.77%. Comparing base (089edf0) to head (864c586).

Files with missing lines	Patch %	Lines
process/core/io/plot/summary.py	0.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4364      +/-   ##
==========================================
- Coverage   48.79%   48.77%   -0.02%     
==========================================
  Files         151      151              
  Lines       29382    29390       +8     
==========================================
  Hits        14336    14336              
- Misses      15046    15054       +8     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.