Update documentation and Colab links from main to develop branch

[gitttt-1234]

Summary

• Updates all GitHub file links in documentation to reference develop branch instead of main
• Updates all Colab notebook "Open in Colab" badges to link to develop branch
• Updates links in GUI code (app.py and dialog.py) to point to develop branch notebooks

Test plan

• Verify all updated Colab links open correctly
• Verify all GitHub file links resolve to valid files on develop branch
• Test "Train on Google Colab" menu option in GUI

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.37%. Comparing base (5f6eb12) to head (ba69a97).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2481      +/-   ##
===========================================
- Coverage    59.40%   59.37%   -0.04%     
===========================================
  Files           68       68              
  Lines        13232    13232              
===========================================
- Hits          7860     7856       -4     
- Misses        5372     5376       +4     

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