chore(deps): upgrade Django to 5.2.17 LTS

[mpast]

Closes #179

Type

• Maintenance/tooling

Summary

• Upgrade Django from 4.2.30 to 5.2.17 LTS.
• Upgrade the maintained Django integrations needed for supported Django 5.2 compatibility.
• Remove the obsolete USE_L10N setting and correct the documented framework version.

Changes

File	Change
requirements.txt	Upgrade Django, asgiref, DRF, django-filter, django-extensions, django-bootstrap4, and django-widget-tweaks.
app/config/settings.py	Remove the setting removed by Django 5.0.
README.md	Document Django 5.2.17 LTS.

Test plan

• Isolated Python 3.12 dependency installation
• pip check
• python manage.py check
• python manage.py makemigrations --check --dry-run
• python manage.py test app — 21 tests passed
• python manage.py collectstatic --noinput
• CI container build and security analysis

Contributor checklist

• Linked approved issue chore(deps): upgrade Django to 5.2.17 LTS #179
• Exactly one type:* label requested
• No shell scripts changed
• Documentation updated
• Conventional commit format
• No Co-Authored-By trailers

Notes

This supersedes #174, whose one-line Django 5.2.16 change fails dependency resolution because it leaves asgiref==3.7.2 pinned.