feat: icon-only toolbar, versioning fixes, history modal, PanelRight repositioning

- Toolbar: remove text labels from all icon buttons (AI, Save, Preview, Convert)
  all buttons now icon-only with title tooltip for accessibility
- Toolbar: reposition PanelRight (info panel toggle) to far right after three-dot menu
- Versioning: decouple getNoteHistory/restoreNoteVersion from global userAISettings.noteHistory
  now checks note.historyEnabled directly — unblocks manual per-note history
- Versioning: add 'Sauvegarder cette version' button in Versions tab of info panel
  calls commitNoteHistory with visual feedback (spinner → success state)
- note-document-info-panel: import commitNoteHistory, add isSavingVersion state
- notes.ts: fix double guard that silently blocked all history operations

architectural-grid (5)/vite.config.ts

@@ -0,0 +1,24 @@
+import tailwindcss from '@tailwindcss/vite';
+import react from '@vitejs/plugin-react';
+import path from 'path';
+import {defineConfig, loadEnv} from 'vite';
+
+export default defineConfig(({mode}) => {
+  const env = loadEnv(mode, '.', '');
+  return {
+    plugins: [react(), tailwindcss()],
+    define: {
+      'process.env.GEMINI_API_KEY': JSON.stringify(env.GEMINI_API_KEY),
+    },
+    resolve: {
+      alias: {
+        '@': path.resolve(__dirname, '.'),
+      },
+    },
+    server: {
+      // HMR is disabled in AI Studio via DISABLE_HMR env var.
+      // Do not modify—file watching is disabled to prevent flickering during agent edits.
+      hmr: process.env.DISABLE_HMR !== 'true',
+    },
+  };
+});