Fix admin route access and backend configuration

- Added /admin redirect to login page in nginx config
- Fixed backend server.js route ordering for proper admin handling
- Updated authentication middleware and routes
- Added user management routes
- Configured PostgreSQL integration
- Updated environment configuration

Sky_Art_shop/.vscode/tasks.json

@@ -0,0 +1,16 @@
+{
+	"version": "2.0.0",
+	"tasks": [
+		{
+			"label": "Build Sky_Art_Shop after nav changes",
+			"type": "shell",
+			"command": "dotnet build",
+			"args": [],
+			"isBackground": false,
+			"problemMatcher": [
+				"$msCompile"
+			],
+			"group": "build"
+		}
+	]
+}