refactor(Index.tsx): simplify tag update logic and improve debounced tag generation

src/pages/Index.tsx

@@ -288,13 +288,9 @@ Keep tags concise, use lowercase, and separate words with hyphens if needed.`);
           addDebugInfo('Auto-generating tags...');
           const tags = await generateTags(content, noteIndex);
           if (noteIndex !== undefined) {
-            // For existing notes
-            const note = noteCache[noteIndex];
-            if (note) {
-              const updatedNote = { ...note, tags };
-              setPreviousNote(updatedNote);
+            // For existing notes - preserve current content from state
+            setPreviousNote(prev => prev ? { ...prev, tags } : null);
             setIsPreviousNoteModified(true);
-            }
           } else {
             // For current note
             setCurrentNoteTags(tags);
@@ -303,7 +299,7 @@ Keep tags concise, use lowercase, and separate words with hyphens if needed.`);
           console.error('Auto tag generation failed:', error);
         }
       }
-    }, 200);
+    }, 300);
     
     setTagGenerationTimeout(timeout);
   };
@@ -2059,7 +2055,10 @@ ${content}${context}`;
                     const updatedNote = { ...previousNote, content: newContent };
                     setPreviousNote(updatedNote);
                     setIsPreviousNoteModified(true);
+                    // Debounced tag generation for previous notes
+                    if (autoGenerateTags) {
                       debouncedGenerateTags(newContent, currentNoteIndex);
+                    }
                     if (newContent.trim() === '') {
                       deleteNote(previousNote.id);
                     }