🏗️(caldav) migrate from davical to sabre/dav

docker/sabredav/sabredav.conf

@@ -0,0 +1,28 @@
+<VirtualHost *:80>
+    ServerName localhost
+    DocumentRoot /var/www/sabredav
+    
+    <Directory /var/www/sabredav>
+        AllowOverride All
+        Require all granted
+        Options -Indexes +FollowSymLinks
+    </Directory>
+    
+    # Set REMOTE_USER from X-Forwarded-User header (set by Django proxy)
+    # This allows sabre/dav to use Apache auth backend
+    <IfModule mod_headers.c>
+        RequestHeader set REMOTE_USER %{HTTP:X-Forwarded-User}e env=HTTP_X_FORWARDED_USER
+    </IfModule>
+    
+    # Rewrite rules for CalDAV
+    RewriteEngine On
+    RewriteCond %{REQUEST_FILENAME} !-f
+    RewriteCond %{REQUEST_FILENAME} !-d
+    RewriteRule ^(.*)$ server.php [QSA,L]
+    
+    # Well-known CalDAV discovery
+    RewriteRule ^\.well-known/caldav / [R=301,L]
+    
+    ErrorLog ${APACHE_LOG_DIR}/sabredav_error.log
+    CustomLog ${APACHE_LOG_DIR}/sabredav_access.log combined
+</VirtualHost>