Generate org-wide sprint and lifetime JSON (#141)

[dhyana6466]

Description

This PR updates the data collection script to generate org-wide sprint and lifetime JSON instead of using a hardcoded list of repositories.
Previously, the script only pulled data from two repos. I changed it so it dynamically fetches all non-archived repositories from the oss-slu organization and generates:

• lifetime_data.json
• sprint_data.json
  I also handled edge cases we ran into while testing:
• Empty repositories (409 errors)
• API instability when fetching PR data
• Avoided crashes by adding safe error handling
  The generated JSON files are placed in Frontend/public/data/ so the homepage can immediately use them without waiting for the first workflow run.

Fixes #141

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

I tested this locally by:

1. Running lifetime mode:
   python -m Backend.dataCollection.collectData --mode lifetime
2. Running sprint mode:
   python -m Backend.dataCollection.collectData --mode sprint
3. Confirming both JSON files were generated inside Frontend/public/data/.
4. Running the frontend locally with npm run dev and verifying that:
   • The Home Page charts render correctly.
   • Data reflects org-wide metrics.
   • No console errors or 404s.

• Test A
• Test B

Test Configuration:

• Python 3.11
• Local dev server (Frontend)
• GitHub token with read access

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshot of Output