Epic 6: Stories 6-2 (Markdown roundtrip) + 6-3 (Brainstorm PPTX + Canvas)

Story 6-2 — Markdown roundtrip export/import:
- lib/editor/markdown-export.ts: tiptapHTMLToMarkdown, markdownToHTML, looksLikeMarkdown
- lib/editor/markdown-paste-extension.ts: TipTap extension paste Markdown → blocs
- note-editor-toolbar.tsx: export .md + import .md (file picker)
- rich-text-editor.tsx: intégration MarkdownPasteExtension
- 40 tests unitaires markdown-export.test.ts

Story 6-3 — Brainstorm PPTX + Canvas:
- lib/brainstorm/export-pptx.ts: génération PPTX 5 slides (pptxgenjs)
- app/api/brainstorm/[sessionId]/export-pptx/route.ts: route POST protégée
- brainstorm-page.tsx: bouton PPTX, auto-select session, fix emoji, fix router.replace
- wave-canvas.tsx: fitTrigger recentrage, légende bas-droite

Onboarding activation wizard (Story 6-1):
- components/onboarding/: wizard multi-étapes, hints éditeur
- app/api/onboarding/: route PATCH onboarding
- prisma/migrations: champs onboarding user

Locales: 15 langues mises à jour (brainstorm, markdown, onboarding keys)
Sprint: 6-1 done, 6-2 review, 6-3 review

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

memento-note/locales/es.json

@@ -2176,7 +2176,12 @@
       "Italiano": "Italiano",
       "Chinois": "Chino",
       "Japonais": "Japonés"
-    }
+    },
+    "exportMarkdown": "Exportar como Markdown",
+    "importMarkdown": "Importar Markdown",
+    "markdownExportSuccess": "Nota exportada como Markdown",
+    "markdownExportError": "Error al exportar la nota",
+    "markdownImportSuccess": "Markdown importado con éxito"
   },
   "brainstorm": {
     "title": "Waves of Thought",
@@ -2306,7 +2311,16 @@
     "ownerBadge": "Owner",
     "waveBadge": "Wave {wave}",
     "quotaGuest": "El anfitrión de la sesión ha alcanzado su límite de IA. Pídele que mejore su plan.",
-    "quotaHost": "Has alcanzado tu límite de IA para este brainstorm. Mejora tu plan para continuar."
+    "quotaHost": "Has alcanzado tu límite de IA para este brainstorm. Mejora tu plan para continuar.",
+    "downloadPptx": "PPTX",
+    "downloadPptxDesc": "Descargar como PowerPoint",
+    "pptxSuccess": "PPTX descargado",
+    "pptxError": "Error al exportar PPTX",
+    "fitToScreen": "Recentrar",
+    "legendWave1": "Variaciones",
+    "legendWave2": "Analogías",
+    "legendWave3": "Disruptivas",
+    "legendConverted": "Convertida"
   },
   "usageMeter": {
     "packName": "AI Discovery Pack",
@@ -2762,5 +2776,96 @@
     "uploadError": "Error al subir",
     "uploadFailed": "Error al subir",
     "uploading": "Subiendo..."
+  },
+  "onboarding": {
+    "welcome_title": "Tu memoria aumentada por IA",
+    "welcome_subtitle": "Momento recuerda lo que olvidas.",
+    "welcome_cta": "Empezar",
+    "skip": "Omitir",
+    "step_notes_title": "Tus notas",
+    "step_notes_empty": "Aún no tienes notas. Importa las tuyas o empieza con ejemplos.",
+    "step_notes_import": "Importar mis notas",
+    "step_notes_demo": "Crear 5 notas de ejemplo",
+    "step_notes_has_notes": "Ya tienes {count} notas. ¡Descubramos la magia!",
+    "step_notes_cta": "Mis notas están listas",
+    "step_aha_title": "Encuentra lo que olvidaste",
+    "step_aha_subtitle": "Haz una pregunta. Encuentra una nota olvidada.",
+    "step_aha_placeholder": "notas sobre productividad...",
+    "step_aha_cta": "Explorar Momento",
+    "progress": "{current} de {total}",
+    "creating_demo_notes": "Creando notas de ejemplo...",
+    "demo_notes_ready": "¡5 notas de ejemplo creadas!",
+    "badge_credits": "⚡ {count} créditos restantes",
+    "badge_upgrade": "Mejorar a Pro →",
+    "no_results": "Sin resultados — intenta otra búsqueda.",
+    "search_credit_used": "1 búsqueda utilizada",
+    "quota_exceeded": "Cuota de búsqueda alcanzada — actualiza a Pro.",
+    "step_aha_search_button": "Buscar",
+    "step_aha_search_aria": "Buscar en tus notas",
+    "step_notes_hint": "💡 Estas notas alimentarán la demo de búsqueda IA en el siguiente paso.",
+    "step_features_title": "Tus superpoderes de IA",
+    "step_features_subtitle": "Elige por dónde empezar.",
+    "step_features_cta": "¡Vamos!",
+    "feature_search_title": "Búsqueda semántica",
+    "feature_search_desc": "Encuentra cualquier nota por significado, no solo por palabras clave.",
+    "feature_flashcards_title": "Tarjetas IA",
+    "feature_flashcards_desc": "Genera tarjetas de repaso SRS desde tus notas con un clic.",
+    "feature_brainstorm_title": "Brainstorming IA",
+    "feature_brainstorm_desc": "Sesiones de lluvia de ideas colaborativas con IA.",
+    "feature_chat_title": "Chatea con tus notas",
+    "feature_chat_desc": "Haz preguntas a tu base de conocimiento personal.",
+    "feature_insights_title": "Perspectivas semánticas",
+    "feature_insights_desc": "Descubre conexiones ocultas entre tus ideas.",
+    "feature_export_title": "Exportación Markdown",
+    "feature_export_desc": "Importa y exporta tus notas en formato Markdown estándar.",
+    "welcome_title_name": "¡Hola {name} 👋",
+    "import_formats": "Formatos aceptados: .md, .txt",
+    "import_error": "No se pudieron importar algunos archivos. Inténtalo de nuevo.",
+    "import_notes_ready": "¡{count} nota(s) importada(s)!",
+    "action_write_title": "Escribe tu primera nota real",
+    "action_write_desc": "Crea una nota y empieza a capturar tus ideas.",
+    "action_flashcards_title": "Genera tus primeras tarjetas",
+    "action_flashcards_desc": "Abre una nota y haz clic en el botón de tarjetas.",
+    "action_brainstorm_title": "Inicia un brainstorming IA",
+    "action_brainstorm_desc": "Explora tus ideas con un agente IA.",
+    "action_try": "Probar",
+    "step_features_cta_all": "¡Todo listo — ¡a sumergirnos!",
+    "action_write_where": "Cierra esto → haz clic en \"+ Nueva nota\" en la barra lateral",
+    "action_flashcards_where": "Cierra esto → abre una nota → botón 🃏 en la barra",
+    "action_brainstorm_where": "Cierra esto → sección \"Canvas\" en la barra lateral",
+    "pill_resume": "✨ Retomar visita",
+    "action_done": "¡Probado!",
+    "editor_hints_title": "Editor tips",
+    "editor_hints_got_it": "Got it!",
+    "hint_slash_title": "\"/\" command — insert blocks",
+    "hint_slash_desc": "In the editor, type \"/\" to open the block menu: heading, list, code block, table, to-do list, and AI commands (Clarify, Shorten, Improve, Expand).",
+    "hint_ai_title": "Built-in AI assistant",
+    "hint_ai_desc": "Click the ✨ button in the toolbar to open the AI panel — ask questions, summarize, rewrite, or brainstorm directly in your note.",
+    "hint_version_title": "Version history",
+    "hint_version_desc": "Click the ⓘ button in the toolbar → \"Versions\" tab. Enable versioning, then save and restore snapshots of your note at any time.",
+    "hint_flashcards_title": "Generate flashcards",
+    "hint_flashcards_desc": "Click the 🎓 button in the toolbar to auto-generate flashcards from your note for spaced repetition review.",
+    "hint_links_title": "Links between notes",
+    "hint_links_desc": "Type \"[[\" in the editor to search and link to another note. Linked notes appear as backlinks at the bottom of the note.",
+    "hint_create_note_title": "Create a note",
+    "hint_create_note_desc": "Click the \"+\" button in the sidebar or press Ctrl+N to create a new note. Then start writing.",
+    "hint_flip_title": "Flip the card",
+    "hint_flip_desc": "Press Space (or click the card) to flip it and reveal the answer.",
+    "hint_rate_keys_title": "Rate with keyboard",
+    "hint_rate_keys_desc": "After flipping, press 1 (Hard), 2 (Difficult), 3 (Good) or 4 (Easy) to rate the card. The SM-2 algorithm schedules your next review automatically.",
+    "hint_generate_from_note_title": "Generate from a note",
+    "hint_generate_from_note_desc": "Open any note and click the 🎓 button in the toolbar to automatically generate flashcards from its content.",
+    "hint_brainstorm_start_title": "Start with an idea",
+    "hint_brainstorm_start_desc": "Type any concept or question in the input field and press Enter. The AI will generate a set of ideas around it.",
+    "hint_brainstorm_deepen_title": "Deepen an idea",
+    "hint_brainstorm_deepen_desc": "Click on any idea card to expand it with sub-ideas and explore it further.",
+    "hint_brainstorm_export_title": "Export your session",
+    "hint_brainstorm_export_desc": "When done, export the entire brainstorm session as a structured note saved to your notebook.",
+    "hint_insights_clusters_title": "Note clusters",
+    "hint_insights_clusters_desc": "Your notes are automatically grouped into thematic clusters. Click a cluster to explore the notes it contains.",
+    "hint_insights_bridge_title": "Bridge notes",
+    "hint_insights_bridge_desc": "Bridge notes connect multiple clusters. They are highlighted because they hold your knowledge graph together.",
+    "hint_insights_refresh_title": "Refresh clusters",
+    "hint_insights_refresh_desc": "If you've added new notes, click the refresh button to recalculate the clusters with the latest content."
   }
-}
+}