feat: Puente Mayúscula-Minúscula + TTS SpeechSynthesis + E2E fixes

app/api/curriculum/grade/route.ts

@@ -0,0 +1,39 @@
+import { NextRequest, NextResponse } from "next/server"
+import { prisma } from "@/lib/db"
+
+export async function POST(request: NextRequest) {
+  try {
+    const { childId, exerciseId, skillCode, correct, promptLevel, responseMs, errorType, stage } = await request.json()
+
+    if (!childId || !exerciseId || !skillCode) {
+      return NextResponse.json({ error: "Missing required fields" }, { status: 400 })
+    }
+
+    const sessionLog = await prisma.sessionLog.findFirst({
+      where: { childId },
+      orderBy: { startedAt: "desc" },
+    })
+
+    if (!sessionLog) {
+      return NextResponse.json({ error: "No active session" }, { status: 400 })
+    }
+
+    await prisma.skillAttempt.create({
+      data: {
+        sessionLogId: sessionLog.id,
+        skillCode,
+        promptLevel: promptLevel ?? 0,
+        correct,
+        responseMs: responseMs ?? null,
+        errorType: errorType ?? null,
+        exerciseId,
+        stage: stage ?? null,
+      },
+    })
+
+    return NextResponse.json({ success: true })
+  } catch (error) {
+    console.error("Curriculum grade error:", error)
+    return NextResponse.json({ error: "Internal error" }, { status: 500 })
+  }
+}