Add webdav module

hosts/nixos/vps/proxy.nix

@@ -149,6 +149,19 @@
             }];
           };
         };
+
+        # WebDAV file server
+        files = {
+          rule = "Host(`files.yanlincs.com`)";
+          entrypoints = "websecure";
+          service = "files";
+          tls = {
+            certResolver = "cloudflare";
+            domains = [{
+              main = "*.yanlincs.com";
+            }];
+          };
+        };
       };
       services = {
         # Redirect service
@@ -249,6 +262,15 @@
             }];
           };
         };
+
+        # WebDAV file server backend (via WireGuard)
+        files = {
+          loadBalancer = {
+            servers = [{
+              url = "http://10.2.2.20:5009";
+            }];
+          };
+        };
       };
       middlewares = {
         # Redirect middleware