feat: монорепо миграция, Discover/SearxNG улучшения

- Миграция на монорепозиторий (apps/frontend, apps/chat-service, etc.)
- Discover: проверка SearxNG, понятное empty state при ненастроенном поиске
- searxng.ts: валидация URL, проверка JSON-ответа, авто-добавление http://
- docker/searxng-config: настройки для JSON API SearxNG

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/frontend/src/components/Settings/Sections/Models/Section.tsx

@@ -0,0 +1,91 @@
+import React, { useState } from 'react';
+import AddProvider from './AddProviderDialog';
+import {
+  ConfigModelProvider,
+  ModelProviderUISection,
+  UIConfigField,
+} from '@/lib/config/types';
+import ModelProvider from './ModelProvider';
+import ModelSelect from './ModelSelect';
+
+const Models = ({
+  fields,
+  values,
+}: {
+  fields: ModelProviderUISection[];
+  values: ConfigModelProvider[];
+}) => {
+  const [providers, setProviders] = useState<ConfigModelProvider[]>(values);
+
+  return (
+    <div className="flex-1 space-y-6 overflow-y-auto py-6">
+      <div className="flex flex-col px-6 gap-y-4">
+        <h3 className="text-xs lg:text-xs text-black/70 dark:text-white/70">
+          Select models
+        </h3>
+        <ModelSelect
+          providers={values.filter((p) =>
+            p.chatModels.some((m) => m.key != 'error'),
+          )}
+          type="chat"
+        />
+        <ModelSelect
+          providers={values.filter((p) =>
+            p.embeddingModels.some((m) => m.key != 'error'),
+          )}
+          type="embedding"
+        />
+      </div>
+      <div className="border-t border-light-200 dark:border-dark-200" />
+      <div className="flex flex-row justify-between items-center px-6 ">
+        <p className="text-xs lg:text-xs text-black/70 dark:text-white/70">
+          Manage connections
+        </p>
+        <AddProvider modelProviders={fields} setProviders={setProviders} />
+      </div>
+      <div className="flex flex-col px-6 gap-y-4">
+        {providers.length === 0 ? (
+          <div className="flex flex-col items-center justify-center py-12 px-4 rounded-lg border-2 border-dashed border-light-200 dark:border-dark-200 bg-light-secondary/10 dark:bg-dark-secondary/10">
+            <div className="p-3 rounded-full bg-sky-500/10 dark:bg-sky-500/10 mb-3">
+              <svg
+                xmlns="http://www.w3.org/2000/svg"
+                className="w-8 h-8 text-sky-500"
+                fill="none"
+                viewBox="0 0 24 24"
+                stroke="currentColor"
+              >
+                <path
+                  strokeLinecap="round"
+                  strokeLinejoin="round"
+                  strokeWidth={2}
+                  d="M13 10V3L4 14h7v7l9-11h-7z"
+                />
+              </svg>
+            </div>
+            <p className="text-sm font-medium text-black/70 dark:text-white/70 mb-1">
+              No connections yet
+            </p>
+            <p className="text-xs text-black/50 dark:text-white/50 text-center max-w-sm mb-4">
+              Add your first connection to start using AI models. Connect to
+              OpenAI, Anthropic, Ollama, and more.
+            </p>
+          </div>
+        ) : (
+          providers.map((provider) => (
+            <ModelProvider
+              key={`provider-${provider.id}`}
+              fields={
+                (fields.find((f) => f.key === provider.type)?.fields ??
+                  []) as UIConfigField[]
+              }
+              modelProvider={provider}
+              setProviders={setProviders}
+            />
+          ))
+        )}
+      </div>
+    </div>
+  );
+};
+
+export default Models;