Change Localize endpoint to use route parameter for key

The Localize endpoint in TestLocalizerController now accepts the "key" parameter as a route parameter instead of a query string. The method signature was updated to use [FromRoute], and the route template was modified to include "{key}". This changes the endpoint usage from /localize?key=de_DE to /localize/de_DE.

EnvelopeGenerator.Web/Controllers/Test/TestLocalizerController.cs

@@ -23,8 +23,8 @@ namespace EnvelopeGenerator.Web.Controllers.Test
             _cultures = cultures;
         }
 
-        [HttpGet]
-        public IActionResult Localize([FromQuery] string key = "de_DE") => Ok(_localizer[key]);
+        [HttpGet("{key}")]
+        public IActionResult Localize([FromRoute] string key) => Ok(_localizer[key]);
 
         [HttpGet("fi-class")]
         public IActionResult GetFIClass(string? lang = null) => lang is null ? Ok(_cultures.FIClasses) : Ok(_cultures[lang]?.FIClass);