feat : MCP server infrastructure setup

Install symfony/mcp-bundle, add STDIO + HTTP transport config,
API token auth on User entity with custom authenticator and firewall,
generate-api-token console command, Nginx /_mcp location, fixture token.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/nginx/conf.d/lesstime.conf

@@ -7,6 +7,11 @@ server {
 
     client_max_body_size 55m;
 
+    location ^~ /_mcp {
+        root /var/www/html/public;
+        try_files $uri /index.php?$query_string;
+    }
+
     location ^~ /api/ {
         root /var/www/html/public;
         try_files $uri /index.php?$query_string;