feat(api): adiciona endpoint para corrigir sessões de chat antigas

- POST /api/admin/fix-chat-sessions
- Chama mutation fixLegacySessions do Convex
- Requer autenticação de admin

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/api/admin/fix-chat-sessions/route.ts

@@ -0,0 +1,30 @@
+import { NextResponse } from "next/server"
+import { ConvexHttpClient } from "convex/browser"
+import { api } from "@/convex/_generated/api"
+import { assertAdminSession } from "@/lib/auth-server"
+
+export const runtime = "nodejs"
+
+export async function POST() {
+  const session = await assertAdminSession()
+  if (!session) {
+    return NextResponse.json({ error: "Não autorizado" }, { status: 401 })
+  }
+
+  const convexUrl = process.env.NEXT_PUBLIC_CONVEX_URL
+  if (!convexUrl) {
+    return NextResponse.json({ error: "CONVEX_URL não configurada" }, { status: 500 })
+  }
+
+  try {
+    const convex = new ConvexHttpClient(convexUrl)
+    const result = await convex.mutation(api.liveChat.fixLegacySessions, {})
+    return NextResponse.json({ success: true, result })
+  } catch (error) {
+    console.error("[fix-chat-sessions] Erro:", error)
+    return NextResponse.json(
+      { error: error instanceof Error ? error.message : "Falha ao corrigir sessões" },
+      { status: 500 }
+    )
+  }
+}