UI Stabilization: Global color theme updates (#75B2D6), AI Assistant styling refactor, and navigation fixes

memento-note/components/note-input.tsx

@@ -1070,13 +1070,22 @@ export function NoteInput({
           noteContent={content}
           noteImages={allImages}
           onApplyToNote={(newContent) => {
+            // Save current state to history before applying AI content
+            setHistory(prev => [...prev.slice(0, historyIndex + 1), { title, content }])
+            setHistoryIndex(prev => prev + 1)
+            
             if (type === 'richtext') {
-              // If content looks like markdown, convert to HTML before injecting into richtext
               const looksLikeMarkdown = /^#{1,6}\s|^[-*]\s|\*\*[^*]+\*\*|^>\s/.test(newContent)
               setContent(looksLikeMarkdown ? markdownToBasicHtml(newContent) : newContent)
             } else {
               setContent(newContent)
             }
+            toast.success(t('ai.appliedToNote'), {
+              action: {
+                label: t('general.undo'),
+                onClick: () => handleUndo()
+              }
+            })
           }}
           lastActionApplied={false}
           notebooks={notebooks.map(nb => ({ id: nb.id, name: nb.name }))}