Migrate frontend to Svelte 5 runes semantics

frontend/src/components/tools/MapperTool.svelte

@@ -163,8 +163,8 @@
                 </div>
             </div>
 
-            <div>
-                <label class="block text-sm font-medium text-gray-700 mb-2">{$t.mapper.source}</label>
+            <fieldset>
+                <legend class="block text-sm font-medium text-gray-700 mb-2">{$t.mapper.source}</legend>
                 <div class="flex space-x-4">
                     <label class="inline-flex items-center">
                         <input type="radio" bind:group={source} value="postgres" class="focus:ring-blue-500 h-4 w-4 text-blue-600 border-gray-300" />
@@ -175,7 +175,7 @@
                         <span class="ml-2 text-sm text-gray-700">{$t.mapper.source_excel}</span>
                     </label>
                 </div>
-            </div>
+            </fieldset>
 
             {#if source === 'postgres'}
                 <div class="space-y-4 p-4 bg-gray-50 rounded-md border border-gray-100">
@@ -220,7 +220,7 @@
             <div class="flex justify-end pt-2 space-x-3">
                 <Button
                     variant="secondary"
-                    on:click={handleGenerateDocs}
+                    onclick={handleGenerateDocs}
                     disabled={isGeneratingDocs || isRunning}
                 >
                     {#if isGeneratingDocs}
@@ -231,7 +231,7 @@
                 </Button>
                 <Button
                     variant="primary"
-                    on:click={handleRunMapper}
+                    onclick={handleRunMapper}
                     disabled={isRunning}
                 >
                     {isRunning ? $t.mapper.starting : $t.mapper.run}