Feature/refactor calendar

[calebj04]

Fix dark mode.
Split CareerDev.tsx into several components to make codebase neater and easier to work with.
Fixed image upload backend by restricting uploading to admin and viewing to authenticated users. (Achieved this by creating policies for the article bucket in supabase).

[Thomasbenissan]

Hey Caleb, nice refactor. Splitting the 900-line monolith into focused components looks great and is so much more readable, and unifying create/edit into a single ArticleModal is clean. Pushed fixes for the following issues directly to the branch:

1. Signed URL stored in DB expired after 60 seconds (fixed)
   uploadArticleImage was generating a signed URL with 60-second expiry and saving it to the article record. After a minute, every article image in the DB was a dead link. Changed it to store the storage path instead. The /api/career-dev-articles GET route now generates fresh signed URLs (1 hour) at read-time, matching how the documents feature works.

2. images.domains is deprecated (fixed)
   Replaced with remotePatterns in next.config.js. Also added **.supabase.co so signed URLs from Supabase storage work with next/image.

3. Typo: MiniCalender.tsx renamed to MiniCalendar.tsx (fixed)

4. Added article bucket to seed.sql (fixed)
   The bucket wasn't in the seed, so local dev setups wouldn't have it. Added it alongside avatars and files.

5. Added "use client" to all new component files (fixed)
   ArticleDetailsModal, ArticleModal, MediaCard, and MiniCalendar all use hooks but were missing the directive. They worked because CareerDev.tsx is a client component, but they should be explicit.

Note: You'll need to make sure the article bucket in the shared Supabase project has the correct RLS policies (upload restricted to admin, viewing restricted to authenticated users). Those policies don't live in the codebase.

Again most of those were minor fixes so all in all looks good!