Story 6-4/6-5: Chat with PDF (done) + PPTX watermark PLG

Story 6-4 — Chat with PDF:
- Feature déjà implémentée (document-qa-overlay.tsx, ingestion, search)
- Marquée done dans sprint-status

Story 6-5 — PPTX Export Watermark (PLG viral loop):
- lib/brainstorm/export-pptx.ts: addWatermark + withWatermark helpers
- lib/ai/tools/pptx.tool.ts: même pattern monkey-patch addSlide
- Watermark 'memento-note.com' 7pt gris bas-droite sur chaque slide
- Zéro modification des 14+ fonctions de slides existantes
- 174 tests passent, aucune erreur TS

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

docs/6-5-pptx-export-watermark.md

@@ -0,0 +1,50 @@
+# Story 6-5 — PPTX Export Watermark (PLG Viral Loop)
+
+**Epic:** 6 — Croissance & Activation (PLG)
+**Status:** done
+
+## User Story
+
+**En tant qu'** utilisateur qui partage une présentation exportée depuis Memento,
+**Je veux** que chaque slide porte discrètement la mention "memento-note.com",
+**Afin que** les destinataires découvrent l'outil et s'inscrivent (boucle virale PLG).
+
+## Acceptance Criteria
+
+- [x] **AC-1** : Chaque slide du PPTX brainstorm contient "memento-note.com" en bas-droite
+- [x] **AC-2** : Chaque slide du PPTX IA (generate_pptx) contient "memento-note.com" en bas-droite
+- [x] **AC-3** : Le watermark est subtil (7pt, gris clair `#B8B0A8`, italique) — visible mais non intrusif
+- [x] **AC-4** : Zéro régression sur la mise en page existante des slides
+
+## Tasks
+
+- [x] T1 — Ajouter helper `addWatermark(slide)` + `withWatermark(pres)` dans `lib/brainstorm/export-pptx.ts`
+- [x] T2 — Appliquer `withWatermark` dans `generateBrainstormPptx` (monkey-patch `pres.addSlide`)
+- [x] T3 — Ajouter helper `addWatermark(slide)` + `withWatermark(pres)` dans `lib/ai/tools/pptx.tool.ts`
+- [x] T4 — Appliquer `withWatermark` dans `buildPresentation` (monkey-patch `pres.addSlide`)
+- [x] T5 — Vérifier TypeScript + 174 tests unitaires passent
+
+## Files Modified
+
+- `memento-note/lib/brainstorm/export-pptx.ts` — helpers `addWatermark` + `withWatermark`, monkey-patch dans `generateBrainstormPptx`
+- `memento-note/lib/ai/tools/pptx.tool.ts` — helpers `addWatermark` + `withWatermark`, monkey-patch dans `buildPresentation`
+
+## Technical Notes
+
+**Pattern monkey-patch :**
+```ts
+function withWatermark(pres: PptxGenJSModule): PptxGenJSModule {
+  const original = pres.addSlide.bind(pres)
+  ;(pres as any).addSlide = (...args: any[]) => {
+    const slide = original(...args)
+    addWatermark(slide)
+    return slide
+  }
+  return pres
+}
+```
+Ce pattern garantit que le watermark est ajouté sur **toutes** les slides sans modifier les 14+ fonctions de construction de slides.
+
+**Design watermark :**
+- Position : `x: 7.0, y: 5.35, w: 2.7, h: 0.2` (bas-droite, slide 10"×5.63")
+- Style : 7pt Arial, couleur `B8B0A8`, italique, alignement droite

docs/sprint-status.yaml

@@ -66,8 +66,8 @@ development_status:
   6-1-onboarding-activation: done             # story-onboarding-activation.md
   6-2-markdown-roundtrip: review        # brief-markdown-roundtrip.md
   6-3-brainstorm-canvas-finalize: review        # story: 6-3-brainstorm-canvas-finalize.md
-  6-4-chat-with-pdf: backlog
-  6-5-pptx-export-watermark: backlog
+  6-4-chat-with-pdf: done                   # already implemented: document-qa-overlay.tsx + document-ingestion + document-search tool
+  6-5-pptx-export-watermark: done              # story: 6-5-pptx-export-watermark.md
   epic-6-retrospective: optional
 
 

memento-note/lib/ai/tools/pptx.tool.ts

@@ -105,6 +105,26 @@ const SHAPE_RECT = 'rect' as const
 const SHAPE_ROUND_RECT = 'roundRect' as const
 const SHAPE_OVAL = 'ellipse' as const
 
+/** PLG viral watermark injected on every slide automatically */
+function addWatermark(slide: any) {
+  slide.addText('memento-note.com', {
+    x: 7.0, y: 5.35, w: 2.7, h: 0.2,
+    fontSize: 7, fontFace: 'Arial', color: 'B8B0A8',
+    align: 'right', italic: true,
+  })
+}
+
+/** Wrap pres.addSlide so every new slide gets the Momento watermark automatically */
+function withWatermark(pres: PptxGenJSModule): PptxGenJSModule {
+  const original = pres.addSlide.bind(pres)
+  ;(pres as any).addSlide = (...args: any[]) => {
+    const slide = original(...args)
+    addWatermark(slide)
+    return slide
+  }
+  return pres
+}
+
 function addBadge(s: any, num: number, accent: string) {
   s.addShape(SHAPE_OVAL, {
     x: 9.3, y: 5.1, w: 0.4, h: 0.4,
@@ -978,7 +998,7 @@ async function buildPresentation(spec: PresentationSpec): Promise<PptxGenJSModul
   const style = STYLES[spec.style || 'soft'] || STYLES.soft!
 
   const PptxGenJS = await getPptxGenClass()
-  const pres = new PptxGenJS()
+  const pres = withWatermark(new PptxGenJS())
   pres.title = spec.title
   pres.author = 'Momento'
   pres.subject = spec.title

memento-note/lib/brainstorm/export-pptx.ts

@@ -66,6 +66,29 @@ function truncate(text: string, max: number): string {
   return text.length > max ? text.slice(0, max - 1) + '…' : text
 }
 
+/**
+ * PLG viral watermark — added to every slide automatically via addSlide monkey-patch.
+ * Subtle branding in bottom-right corner to drive organic acquisition.
+ */
+function addWatermark(slide: any) {
+  slide.addText('memento-note.com', {
+    x: 7.0, y: 5.35, w: 2.7, h: 0.2,
+    fontSize: 7, fontFace: 'Arial', color: 'B8B0A8',
+    align: 'right', italic: true,
+  })
+}
+
+/** Wrap pres.addSlide so every new slide gets the Momento watermark automatically */
+function withWatermark(pres: PptxGenJSModule): PptxGenJSModule {
+  const original = pres.addSlide.bind(pres)
+  ;(pres as any).addSlide = (...args: any[]) => {
+    const slide = original(...args)
+    addWatermark(slide)
+    return slide
+  }
+  return pres
+}
+
 // Add a consistent slide background
 function addBg(slide: any) {
   slide.background = { color: T.bg }
@@ -279,7 +302,7 @@ function buildSummarySlide(pres: PptxGenJSModule, session: SessionLike, stats: {
 
 export async function generateBrainstormPptx(session: SessionLike): Promise<{ buffer: Buffer; filename: string }> {
   const PptxGenJS = await getPptxGenClass()
-  const pres = new PptxGenJS()
+  const pres = withWatermark(new PptxGenJS())
 
   pres.layout = 'LAYOUT_WIDE'
   pres.author = 'Momento'