Move portfolio case studies to data-driven template system and archive old individual files

.htaccess

@@ -9,6 +9,12 @@ RewriteEngine On
 RewriteCond %{REQUEST_FILENAME} !-d
 RewriteRule ^(.*)/$ /$1 [L,R=301]
 
+# Portfolio index
+RewriteRule ^portfolio$ /portfolio.php [L,QSA]
+
+# Portfolio case study pages: /portfolio/{slug} → portfolio-page.php
+RewriteRule ^portfolio/([a-z0-9\-]+)$ /portfolio-page.php?slug=$1 [L,QSA]
+
 # Security headers
 <IfModule mod_headers.c>
     Header set X-Content-Type-Options "nosniff"