fix: ajoute slide_generate et excalidraw_generate dans VALID_FEATURES

Sans ça isValidFeature retourne false → QuotaExceededError immédiat

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

memento-note/lib/quota-utils.ts

@@ -8,6 +8,8 @@ export const VALID_FEATURES = [
   'brainstorm_expand',
   'brainstorm_enrich',
   'suggest_charts',
+  'slide_generate',
+  'excalidraw_generate',
 ] as const;
 
 export type FeatureName = (typeof VALID_FEATURES)[number];