feat: add StorageManager, VisualizationManager, UIManager, EditorManager, and update PanelResizer for improved snippet handling and visualization

src/UIManager.js

@@ -0,0 +1,44 @@
+export class UIManager {
+    constructor(snippetManager) {
+        this.snippetManager = snippetManager;
+        this.setupEventListeners();
+    }
+
+    setupEventListeners() {
+        document.getElementById('new-snippet').onclick = () => this.snippetManager.createNewSnippet();
+        document.getElementById('save-snippet').onclick = () => this.snippetManager.saveCurrentSnippet();
+        document.getElementById('version-switch').onclick = () => {
+            this.snippetManager.loadSnippet(this.snippetManager.currentSnippetId, !this.snippetManager.isDraftVersion);
+        };
+    }
+
+    renderSnippetList(snippets, currentSnippetId) {
+        const container = document.getElementById('snippet-list');
+        container.innerHTML = '';
+
+        snippets.forEach(snippet => {
+            const div = document.createElement('div');
+            div.className = `snippet-item ${snippet.id === currentSnippetId ? 'active' : ''}`;
+            const hasChanges = this.snippetManager.hasDraftChanges(snippet.id);
+            const indicator = hasChanges ? '🟡' : '🟢';
+            div.textContent = `${indicator} ${snippet.name}`;
+            div.onclick = () => this.snippetManager.loadSnippet(snippet.id);
+            container.appendChild(div);
+        });
+    }
+
+    updateSaveButton(hasUnsavedChanges) {
+        const saveButton = document.getElementById('save-snippet');
+        saveButton.disabled = !hasUnsavedChanges;
+    }
+
+    updateVersionSwitch(currentSnippetId, isDraftVersion, hasDraftChanges) {
+        const versionSwitch = document.getElementById('version-switch');
+        if (!versionSwitch) return;
+
+        versionSwitch.style.display = hasDraftChanges ? 'block' : 'none';
+        versionSwitch.textContent = isDraftVersion ? 
+            'View Saved Version (Read-only)' : 
+            'Switch to Draft Version (Editable)';
+    }
+}