fix: chart/diagram fond cohérent avec le thème + slides strictement proportionnels

- slides-renderer: chart et diagram utilisent bg/text/muted du thème
  (plus de fond #111827 forcé)
- slides.tool: prompt ultra-clair (<50 mots = max 3 slides)
  + cappedSlides.slice(0,8) côté serveur comme filet de sécurité

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

memento-note/components/lab/slides-renderer.tsx

@@ -390,10 +390,11 @@ function SlideContent({ slide, index, palette, radius }: { slide: SlideSpec; ind
     // ── CHART ────────────────────────────────────────────────────────────
     case 'chart':
       return (
-        <div style={{ width: '100%', height: '100%', display: 'flex', flexDirection: 'column', padding: '48px 60px', background: isDark ? palette.bg : '#111827', textAlign: 'left' }}>
-          <h2 style={{ margin: 0, fontSize: 30, fontWeight: 800, letterSpacing: '-0.04em', color: '#fff' }}>{slide.title}</h2>
-          {slide.subtitle && <p style={{ margin: '6px 0 0', fontSize: 15, color: 'rgba(255,255,255,0.5)' }}>{slide.subtitle}</p>}
-          <div style={{ flex: 1, marginTop: 24 }}>
+        <div style={{ width: '100%', height: '100%', display: 'flex', flexDirection: 'column', padding: '48px 60px', textAlign: 'left' }}>
+          <h2 style={{ margin: 0, fontSize: 30, fontWeight: 800, letterSpacing: '-0.04em', color: text }}>{slide.title}</h2>
+          {slide.subtitle && <p style={{ margin: '6px 0 0', fontSize: 15, color: muted }}>{slide.subtitle}</p>}
+          <div style={accentBar} />
+          <div style={{ flex: 1 }}>
             <SlideChart slide={slide} />
           </div>
         </div>
@@ -402,11 +403,12 @@ function SlideContent({ slide, index, palette, radius }: { slide: SlideSpec; ind
     // ── DIAGRAM ──────────────────────────────────────────────────────────
     case 'diagram':
       return (
-        <div style={{ width: '100%', height: '100%', display: 'flex', flexDirection: 'column', padding: '48px 60px', background: isDark ? palette.bg : '#111827', textAlign: 'left' }}>
-          <h2 style={{ margin: 0, fontSize: 30, fontWeight: 800, letterSpacing: '-0.04em', color: '#fff' }}>{slide.title}</h2>
-          {slide.subtitle && <p style={{ margin: '6px 0 0', fontSize: 15, color: 'rgba(255,255,255,0.5)' }}>{slide.subtitle}</p>}
-          <div style={{ flex: 1, marginTop: 20, overflow: 'hidden', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
-            {slide.mermaid ? <MermaidDiagram chart={slide.mermaid} isDark={true} /> : <p style={{ color: 'rgba(255,255,255,0.3)' }}>No diagram</p>}
+        <div style={{ width: '100%', height: '100%', display: 'flex', flexDirection: 'column', padding: '48px 60px', textAlign: 'left' }}>
+          <h2 style={{ margin: 0, fontSize: 30, fontWeight: 800, letterSpacing: '-0.04em', color: text }}>{slide.title}</h2>
+          {slide.subtitle && <p style={{ margin: '6px 0 0', fontSize: 15, color: muted }}>{slide.subtitle}</p>}
+          <div style={accentBar} />
+          <div style={{ flex: 1, overflow: 'hidden', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>
+            {slide.mermaid ? <MermaidDiagram chart={slide.mermaid} isDark={isDark} /> : <p style={{ color: muted }}>No diagram</p>}
           </div>
         </div>
       )

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

@@ -45,17 +45,16 @@ Available slide types:
 - "summary": title, items[] (conclusion with checkmarks)
 
 RULES:
-- MAXIMUM 8 slides total — NEVER exceed 8, even for long notes
-- Count only plain-text words, ignore markdown syntax, URLs, and metadata
-- For short notes (<100 plain words): 3-4 slides max
-- For medium notes (100-300 plain words): 5-6 slides max
-- For any other note: 7-8 slides max — HARD LIMIT
+- Count the plain-text words in the note (ignore markdown, URLs, metadata, headers)
+- <50 words → 2-3 slides MAXIMUM (title + 1 content + summary)
+- 50-150 words → 3-4 slides max
+- 150-400 words → 5-6 slides max
+- >400 words → 7-8 slides max — HARD LIMIT, NEVER exceed 8
 - First slide MUST be type "title"
 - Last slide MUST be type "summary"
-- Include at most 1 "chart" or "stats" slide — only if real numeric data exists in the note
+- Include "chart" ONLY if real numeric data exists in the note — otherwise FORBIDDEN
 - Use VARIED types — never 2 identical types in a row
-- All text content must come from the source notes (never invent data)
-- Each bullet/card must be a real sentence (15+ words, not generic)`,
+- All text must come from the source note — never invent data`,
       inputSchema: z.object({
         title: z.string().describe('Short presentation title (6 words max)'),
         theme: z.string().optional().describe('Visual recipe: architectural-saas, midnight-cathedral, aurora-borealis, venture-pitch, clinical-precision, coastal-morning, etc.'),
@@ -64,9 +63,11 @@ RULES:
 
       execute: async ({ title, theme, slides }) => {
         try {
-          console.log('[Slides Tool] Building presentation:', title, '| Slides:', slides.length, '| Theme:', theme)
+          // Hard cap: never more than 8 slides regardless of what the model outputs
+          const cappedSlides = slides.slice(0, 8)
+          console.log('[Slides Tool] Building presentation:', title, '| Slides:', cappedSlides.length, '| Theme:', theme)
 
-          const html = buildPresentationHTML({ title, theme, slides: slides as any })
+          const html = buildPresentationHTML({ title, theme, slides: cappedSlides as any })
 
           const canvas = await prisma.canvas.create({
             data: {
@@ -75,15 +76,15 @@ RULES:
                 type: 'slides',
                 title: title || 'Présentation',
                 html,
-                slideCount: slides.length,
+                slideCount: cappedSlides.length,
                 theme: theme || 'architectural-saas',
-                spec: { title, theme, slides },
+                spec: { title, theme, slides: cappedSlides },
               }),
               userId: ctx.userId,
             },
           })
 
-          console.log('[Slides Tool] Canvas created:', canvas.id, '| Slides:', slides.length, '| Size:', Math.round(html.length / 1024), 'KB')
+          console.log('[Slides Tool] Canvas created:', canvas.id, '| Slides:', cappedSlides.length, '| Size:', Math.round(html.length / 1024), 'KB')
 
           // Decrement slide_generate quota after successful canvas creation
           incrementUsageAsync(ctx.userId, 'slide_generate')
@@ -94,7 +95,7 @@ RULES:
               data: {
                 status: 'success',
                 result: canvas.id,
-                log: `Slides generated: ${slides.length} slides, ${Math.round(html.length / 1024)}KB`,
+                log: `Slides generated: ${cappedSlides.length} slides, ${Math.round(html.length / 1024)}KB`,
               },
             }).catch(err => console.error('[Slides Tool] Failed to update action status:', err))
           }
@@ -103,8 +104,8 @@ RULES:
             success: true,
             canvasId: canvas.id,
             canvasName: canvas.name,
-            slideCount: slides.length,
-            message: `Presentation "${canvas.name}" created with ${slides.length} slides.`,
+            slideCount: cappedSlides.length,
+            message: `Presentation "${canvas.name}" created with ${cappedSlides.length} slides.`,
           }
         } catch (e: any) {
           console.error('[Slides Tool] FATAL:', e)