feat: Implement LLM provider deletion and refactor ConfigManager to preserve unknown payload sections.

frontend/src/components/llm/ProviderConfig.svelte

@@ -31,6 +31,7 @@
   let testStatus = $state({ type: "", message: "" });
   let isTesting = $state(false);
   let togglingProviderIds = $state(new Set());
+  let deletingProviderIds = $state(new Set());
 
   function isMultimodalModel(modelName) {
     const token = (modelName || "").toLowerCase();
@@ -155,6 +156,38 @@
       onSave();
     }
   }
+
+  async function handleDelete(provider) {
+    if (deletingProviderIds.has(provider.id)) return;
+    if (
+      !confirm(
+        $t.llm.delete_confirm.replace("{name}", provider.name || provider.id),
+      )
+    ) {
+      return;
+    }
+
+    deletingProviderIds.add(provider.id);
+    deletingProviderIds = new Set(deletingProviderIds);
+
+    try {
+      await requestApi(`/llm/providers/${provider.id}`, "DELETE");
+      providers = providers.filter(({ id }) => id !== provider.id);
+      addToast($t.llm.delete_success.replace("{name}", provider.name), "success");
+      onSave();
+    } catch (err) {
+      addToast(
+        $t.llm.delete_failed.replace(
+          "{error}",
+          err?.message || $t.common.error,
+        ),
+        "error",
+      );
+    } finally {
+      deletingProviderIds.delete(provider.id);
+      deletingProviderIds = new Set(deletingProviderIds);
+    }
+  }
 </script>
 
 <div class="p-4">
@@ -345,11 +378,23 @@
           >
             {$t.common.edit}
           </button>
+          <button
+            type="button"
+            class="text-sm text-red-600 hover:underline"
+            onclick={() => handleDelete(provider)}
+            disabled={deletingProviderIds.has(provider.id)}
+          >
+            {#if deletingProviderIds.has(provider.id)}
+              ...
+            {:else}
+              {$t.common.delete}
+            {/if}
+          </button>
           <button
             type="button"
             class={`text-sm ${provider.is_active ? "text-orange-600" : "text-green-600"} hover:underline`}
             onclick={() => toggleActive(provider)}
-            disabled={togglingProviderIds.has(provider.id)}
+            disabled={togglingProviderIds.has(provider.id) || deletingProviderIds.has(provider.id)}
           >
             {#if togglingProviderIds.has(provider.id)}
               ...

frontend/src/components/llm/__tests__/provider_config.integration.test.js

@@ -1,7 +1,7 @@
 // [DEF:frontend.src.components.llm.__tests__.provider_config_integration:Module]
 // @TIER: STANDARD
-// @SEMANTICS: llm, provider-config, integration-test, edit-flow
-// @PURPOSE: Protect edit-button interaction contract in LLM provider settings UI.
+// @SEMANTICS: llm, provider-config, integration-test, edit-flow, delete-flow
+// @PURPOSE: Protect edit and delete interaction contracts in LLM provider settings UI.
 // @LAYER: UI Tests
 // @RELATION: VERIFIES -> frontend/src/components/llm/ProviderConfig.svelte
 // @INVARIANT: Edit action keeps explicit click handler and opens normalized edit form.
@@ -17,7 +17,7 @@ const COMPONENT_PATH = path.resolve(
 
 // [DEF:provider_config_edit_contract_tests:Function]
 // @TIER: STANDARD
-// @PURPOSE: Validate edit button handler wiring and normalized edit form state mapping.
+// @PURPOSE: Validate edit and delete handler wiring plus normalized edit form state mapping.
 // @PRE: ProviderConfig component source exists in expected path.
 // @POST: Contract checks ensure edit click cannot degrade into no-op flow.
 describe('ProviderConfig edit interaction contract', () => {
@@ -25,9 +25,7 @@ describe('ProviderConfig edit interaction contract', () => {
     const source = fs.readFileSync(COMPONENT_PATH, 'utf-8');
 
     expect(source).toContain('type="button"');
-    expect(source).toContain(
-      "on:click|preventDefault|stopPropagation={() => handleEdit(provider)}",
-    );
+    expect(source).toContain('onclick={() => handleEdit(provider)}');
   });
 
   it('normalizes provider payload into editable form shape', () => {
@@ -39,6 +37,15 @@ describe('ProviderConfig edit interaction contract', () => {
     expect(source).toContain('default_model: provider?.default_model ?? "gpt-4o"');
     expect(source).toContain('showForm = true;');
   });
+
+  it('keeps explicit delete flow with confirmation and delete request', () => {
+    const source = fs.readFileSync(COMPONENT_PATH, 'utf-8');
+
+    expect(source).toContain('async function handleDelete(provider)');
+    expect(source).toContain('$t.llm.delete_confirm.replace("{name}", provider.name || provider.id)');
+    expect(source).toContain('await requestApi(`/llm/providers/${provider.id}`, "DELETE")');
+    expect(source).toContain('onclick={() => handleDelete(provider)}');
+  });
 });
 // [/DEF:provider_config_edit_contract_tests:Function]
 // [/DEF:frontend.src.components.llm.__tests__.provider_config_integration:Module]

frontend/src/lib/i18n/locales/en.json

@@ -111,6 +111,9 @@
     "connection_success": "Connection successful!",
     "connection_failed": "Connection failed: {error}",
     "no_providers": "No providers configured.",
+    "delete_confirm": "Delete LLM provider \"{name}\"?",
+    "delete_success": "Provider \"{name}\" deleted.",
+    "delete_failed": "Failed to delete provider: {error}",
     "multimodal": "Multimodal",
     "text_only": "Text only",
     "doc_preview_title": "Documentation Preview",

frontend/src/lib/i18n/locales/ru.json

@@ -111,6 +111,9 @@
     "connection_success": "Подключение успешно!",
     "connection_failed": "Ошибка подключения: {error}",
     "no_providers": "Провайдеры не настроены.",
+    "delete_confirm": "Удалить LLM-провайдера \"{name}\"?",
+    "delete_success": "Провайдер \"{name}\" удалён.",
+    "delete_failed": "Не удалось удалить провайдера: {error}",
     "multimodal": "Мультимодальная",
     "text_only": "Только текст",
     "doc_preview_title": "Предпросмотр документации",