bakerydemo: Add missing BreadIngredients and assign to breads (#564)

[pratyushjha06]

Fixes #564

Summary

This PR adds missing ingredients data to bread pages in the bakerydemo fixture.

Changes Made

• Added 80+ BreadIngredient entries to bakerydemo.json fixture
• Assigned 6-12 realistic ingredients to each BreadPage based on bread type
• Created seed_ingredients.py management command for reproducible ingredient assignment
• Validated fixture with jsonlint.com to ensure proper JSON formatting

Testing

• ✅ Tested locally on Windows with Django 5.x
• ✅ Verified all bread detail pages now display ingredient lists
• ✅ Confirmed ingredients appear correctly in Django admin
• ✅ Fixture loads without errors using python manage.py loaddata bakerydemo.json

Notes

• Minor encoding workarounds applied for Windows compatibility
• All bread pages now show non-empty ingredient lists by default
• Ready for review and testing on Linux/macOS environments

Screenshots