Add pagination, year filtering, and styling enhancements to blog and events pages

[Phinart98]

closes #42

• Add pagination (12 posts/page for blog, 15 events/page)
• Add year filtering with scroll position preservation
• Add header images with overlays on index pages
• Add Upcoming Events section with purple sidebar cards
• Fix rich text formatting by installing Tailwind Typography plugin
• Add management command to generate test data

[Phinart98]

Hello @lwasser ,
I have made changes to the blog and event pages that significantly improve the formatting and allow you to add images as well. You can now filter posts by year, and the pages have been paginated too.

Additionally, using the resource from the Django documentation shared by @banesullivan, I have written a script that allows you to run a command to generate dummy posts, making it easier for you to test these changes. I think that can help with migrating the actual blog posts too, but we will have to think a bit more deeply about that😅.

Here's how to test:
Setup (one-time):

1. Install dependencies: npm install

2. Rebuild CSS: npm run build-prod
   (These will help show the formatting changes you apply in the CMS - headings, bullet points, etc).

Testing:

1. Generate test data: uv run python manage.py create_dummy_posts
   - Options: --blog-posts=30 --events=25 to specify counts
   - Use --delete flag to clear any existing dummy data

2. Visit /blog/ and /events/ to see pagination and year filtering.

3. In Wagtail CMS, create or edit a blog post and add rich text formatting (bullets, headings, bold text, etc.) and a header image to verify the Tailwind Typography styling works correctly