feat: page interactive, démos Play/Step et simulateur Carnot

Ajoute le pipeline PageSpec (validation, rendu, publication /p/{slug}),
les démos TipTap /demo, et le simulateur Carnot (modes frigo/PAC/moteur,
énergie kJ vs puissance W, unités K/°C/°F) avec correctifs d’équations KaTeX.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/app/api/ai/interactive-demo/route.ts

@@ -0,0 +1,125 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { z } from 'zod'
+import { auth } from '@/auth'
+import { getSystemConfig } from '@/lib/config'
+import { reserveAiUsageOrThrow } from '@/lib/ai-quota'
+import { QuotaExceededError, QuotaServiceUnavailableError } from '@/lib/entitlements'
+import { hasUserAiConsent, aiConsentForbiddenResponse } from '@/lib/consent/server-consent'
+import { getSlidesProvider } from '@/lib/ai/factory'
+import { generateInteractiveDemoFromContent } from '@/lib/ai/services/interactive-demo-generate.service'
+
+export const maxDuration = 180
+
+const requestSchema = z.object({
+  content: z.string().min(20),
+  selection: z.string().optional().nullable(),
+  lang: z.string().optional(),
+  noteId: z.string().optional(),
+})
+
+function stripHtml(html: string): string {
+  return html
+    .replace(/<[^>]+>/g, ' ')
+    .replace(/&nbsp;/g, ' ')
+    .replace(/&amp;/g, '&')
+    .replace(/&lt;/g, '<')
+    .replace(/&gt;/g, '>')
+    .replace(/&quot;/g, '"')
+    .replace(/&#39;/g, "'")
+    .replace(/\s+/g, ' ')
+    .trim()
+}
+
+export async function POST(req: NextRequest) {
+  try {
+    const session = await auth()
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+    }
+
+    if (!(await hasUserAiConsent())) {
+      return aiConsentForbiddenResponse()
+    }
+
+    const body = await req.json()
+    const parsed = requestSchema.parse(body)
+    // Keep raw HTML/markdown so formula extractors see $...$ / KaTeX like slides
+    const sourceRaw = parsed.selection?.trim() || parsed.content
+    const sourcePlain = stripHtml(sourceRaw)
+    const wordCount = sourcePlain.split(/\s+/).filter(Boolean).length
+    if (wordCount < 20) {
+      return NextResponse.json(
+        {
+          error:
+            'Sélectionne au moins ~20 mots de contenu pour générer une démo interactive',
+        },
+        { status: 400 }
+      )
+    }
+
+    try {
+      await reserveAiUsageOrThrow(session.user.id, 'interactive_demo', {
+        lane: 'chat',
+      })
+    } catch (err) {
+      if (err instanceof QuotaExceededError) {
+        return NextResponse.json(err.toJSON(), { status: 402 })
+      }
+      if (
+        err instanceof QuotaServiceUnavailableError ||
+        process.env.NODE_ENV === 'production'
+      ) {
+        return NextResponse.json(
+          { error: 'QUOTA_SERVICE_UNAVAILABLE' },
+          { status: 503 }
+        )
+      }
+      console.error('[/api/ai/interactive-demo] Quota check error (fail-open):', err)
+    }
+
+    const config = await getSystemConfig()
+    const lang = parsed.lang || 'fr'
+    // Same admin model as slide decks (AI_PROVIDER_SLIDES / AI_MODEL_SLIDES → chat fallback)
+    const provider = getSlidesProvider(config)
+
+    const result = await generateInteractiveDemoFromContent({
+      content: sourceRaw,
+      lang,
+      provider,
+    })
+
+    if (!result.ok) {
+      const first = result.issues[0]
+      const detail = first
+        ? `${first.path ? first.path + ': ' : ''}${first.message}`
+        : ''
+      console.error(
+        '[/api/ai/interactive-demo] validation failed after repairs',
+        result.issues.slice(0, 10)
+      )
+      return NextResponse.json(
+        {
+          error: detail
+            ? `Démo invalide après correction — ${detail}`
+            : 'La génération a produit un JSON invalide après correction',
+          issues: result.issues.slice(0, 10),
+          attempts: result.attempts,
+        },
+        { status: 422 }
+      )
+    }
+
+    return NextResponse.json({
+      demo: result.demo,
+      attempts: result.attempts,
+    })
+  } catch (error: unknown) {
+    if (error instanceof z.ZodError) {
+      return NextResponse.json({ error: error.issues }, { status: 400 })
+    }
+    const message =
+      error instanceof Error ? error.message : 'Erreur génération interactive demo'
+    console.error('[/api/ai/interactive-demo]', error)
+    return NextResponse.json({ error: message }, { status: 500 })
+  }
+}