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/chat-service/src/lib/agents/search/classifier.ts

@@ -0,0 +1,53 @@
+import z from 'zod';
+import { ClassifierInput } from './types';
+import { classifierPrompt } from '@/lib/prompts/search/classifier';
+import formatChatHistoryAsString from '@/lib/utils/formatHistory';
+
+const schema = z.object({
+  classification: z.object({
+    skipSearch: z
+      .boolean()
+      .describe('Indicates whether to skip the search step.'),
+    personalSearch: z
+      .boolean()
+      .describe('Indicates whether to perform a personal search.'),
+    academicSearch: z
+      .boolean()
+      .describe('Indicates whether to perform an academic search.'),
+    discussionSearch: z
+      .boolean()
+      .describe('Indicates whether to perform a discussion search.'),
+    showWeatherWidget: z
+      .boolean()
+      .describe('Indicates whether to show the weather widget.'),
+    showStockWidget: z
+      .boolean()
+      .describe('Indicates whether to show the stock widget.'),
+    showCalculationWidget: z
+      .boolean()
+      .describe('Indicates whether to show the calculation widget.'),
+  }),
+  standaloneFollowUp: z
+    .string()
+    .describe(
+      "A self-contained, context-independent reformulation of the user's question.",
+    ),
+});
+
+export const classify = async (input: ClassifierInput) => {
+  const output = await input.llm.generateObject<typeof schema>({
+    messages: [
+      {
+        role: 'system',
+        content: classifierPrompt,
+      },
+      {
+        role: 'user',
+        content: `<conversation_history>\n${formatChatHistoryAsString(input.chatHistory)}\n</conversation_history>\n<user_query>\n${input.query}\n</user_query>`,
+      },
+    ],
+    schema,
+  });
+
+  return output;
+};