fix: remove fake prompt for document-only sends

- Don't inject "What is this document about?" — model uses context
  instruction from system prompt
- Use document name as chat title when no text input
- Always query RAG when sources are enabled, even without text

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: NorbertKlockiewicz

components/chat-screen/ChatScreen.tsx

@@ -114,15 +114,13 @@ export default function ChatScreen({
       isGenerating
     )
       return;
-    // If no text but documents attached, ask model to describe the document
-    const effectiveInput =
-      userInput.trim() || (hasDocuments ? 'What is this document about?' : '');
-
     if (!(await checkIfChatExists(db, chatId!))) {
+      const docName = attachments?.find((a) => a.type === 'document')?.name;
+      const titleSource = userInput.trim() || docName || 'New chat';
       const newChatTitle =
-        effectiveInput.length > 25
-          ? effectiveInput.slice(0, 25) + '...'
-          : effectiveInput;
+        titleSource.length > 25
+          ? titleSource.slice(0, 25) + '...'
+          : titleSource;
       await addChat(newChatTitle, model!.id);
     }
 
@@ -184,9 +182,9 @@ export default function ChatScreen({
       freshChat?.enabledSources || freshPhantom?.enabledSources || [];
     console.log('[SEND] currentEnabledSources (after):', currentEnabledSources);
 
-    if (currentEnabledSources.length > 0 && effectiveInput) {
+    if (currentEnabledSources.length > 0) {
       const ragContext = await prepareContext(
-        effectiveInput,
+        userInput || 'document summary',
         currentEnabledSources,
         vectorStore!
       );
@@ -203,9 +201,9 @@ export default function ChatScreen({
       thinkingEnabled: chatSettings.thinkingEnabled,
     };
 
-    console.log('[SEND] effectiveInput:', effectiveInput);
+    console.log('[SEND] userInput:', userInput);
     console.log('[SEND] settings:', JSON.stringify(settings));
-    await sendChatMessage(effectiveInput, chatId!, context, settings, imagePath);
+    await sendChatMessage(userInput, chatId!, context, settings, imagePath);
   };
 
   const handleSelectModel = async (selectedModel: Model) => {