fix: enforce security profile language across DAVE

test/telegram-chat.test.mjs

@@ -44,6 +44,24 @@ test('Telegram AI chat reports missing LLM configuration', async () => {
   assert.match(await assistant.reply('hello', { chatId: 1 }), /unavailable/i);
 });
 
+test('Telegram AI chat enforces the encrypted profile language in provider prompts', async () => {
+  const calls = [];
+  const assistant = new TelegramChatAssistant({
+    provider: {
+      isConfigured: true,
+      async complete(systemPrompt, userMessage) {
+        calls.push({ systemPrompt, userMessage });
+        return { text: 'Antwort auf Deutsch.' };
+      },
+    },
+    getPreferredLanguage: () => 'de',
+  });
+
+  assert.equal(await assistant.reply('Kurzer Lagecheck', { chatId: 42 }), 'Antwort auf Deutsch.');
+  assert.match(calls[0].systemPrompt, /REQUIRED RESPONSE LANGUAGE: German \(de\)/);
+  assert.match(calls[0].userMessage, /All user-visible prose in the final answer must be German/);
+});
+
 test('Telegram chat context is compact and operationally useful', () => {
   const context = JSON.parse(buildTelegramChatContext({
     meta: { generatedAt: '2026-07-05T10:00:00Z' },