feat: redesign homepage with Radix UI and add dev environment defaults

- Replace title/tagline homepage with social profile design
- Add Radix UI Themes + icon libraries for modern UI components
- Provide sensible dev defaults for DB/secrets (no .env required)
- Add production safety checks for critical env vars
- Make optional features (cron, healthcheck) gracefully skip when unconfigured

.env.example

@@ -1,25 +1,23 @@
-# Since .env is gitignored, you can use .env.example to build a new `.env` file when you clone the repo.
-# Keep this file up-to-date when you add new variables to `.env`.
+# Environment variables for xevion.dev
+# Dev defaults are available - no .env file needed for basic development
+# See schema in /env/schema.mjs
 
-# This file will be committed to version control, so make sure not to have any secrets in it.
-# If you are cloning this repo, create a copy of this file named `.env` and populate it with your secrets.
-
-# When adding additional env variables, the schema in /env/schema.mjs should be updated accordingly
-
-# Payload CMS
+# Payload CMS (dev defaults match docker-compose credentials)
 PAYLOAD_SECRET=your-secret-key-here
 DATABASE_URI=postgresql://xevion:xevion_dev_password@localhost:5432/xevion_dev
-PAYLOAD_REVALIDATE_KEY=your-revalidate-key-here
 
-# GitHub API (for cron job)
+# Optional - enables /api/cron/updated endpoint
 GITHUB_API_TOKEN=
 
-# API Secrets
+# Optional - enables /api/healthcheck endpoint  
 HEALTHCHECK_SECRET=
+
+# Optional - auth for /api/cron/updated (skipped in dev)
 CRON_SECRET=
 
 # Optional
+PAYLOAD_REVALIDATE_KEY=
 TITLE=
 
-# Node environment
+# Auto-detected, usually don't need to set
 NODE_ENV=development