fix: Resolve Tailwind CSS v4/v3 compatibility issues for deployment

- Downgrade @astrojs/tailwind to v5.1.1 for v3 compatibility
- Remove @tailwindcss/vite dependency (v4 specific)
- Update tailwindcss to v3.4.17
- Fix astro.config.mjs to use standard Tailwind integration
- Update CSS imports to use v3 @tailwind directives

Fixes server deployment build failures due to dependency conflicts.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

astro.config.mjs

@@ -2,7 +2,7 @@
 import { defineConfig } from 'astro/config';
 
 import react from '@astrojs/react';
-import tailwindcss from '@tailwindcss/vite';
+import tailwind from '@astrojs/tailwind';
 import node from '@astrojs/node';
 import sentry from '@sentry/astro';
 
@@ -11,6 +11,7 @@ export default defineConfig({
   output: 'server',
   integrations: [
     react(),
+    tailwind(),
     sentry({
       dsn: process.env.SENTRY_DSN,
       environment: process.env.NODE_ENV || 'development',
@@ -21,9 +22,6 @@ export default defineConfig({
     mode: 'standalone'
   }),
 
-  vite: {
-    plugins: [tailwindcss()]
-  },
 
   server: {
     port: 4321,