Move round scheduler in-app via instrumentation.ts, remove cron endpoint

Round open/close scheduling now runs as a 60s setInterval inside the
app process (via instrumentation.ts register hook) instead of needing
an external crontab. Removed the /api/cron/round-scheduler endpoint.

- DRAFT rounds auto-activate when windowOpenAt arrives
- ACTIVE rounds auto-close when windowCloseAt passes
- Uses existing activateRound/closeRound from round-engine

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/api/cron/round-scheduler/route.ts

@@ -1,82 +0,0 @@
-import { NextResponse } from 'next/server'
-import type { NextRequest } from 'next/server'
-import { prisma } from '@/lib/prisma'
-import { activateRound, closeRound } from '@/server/services/round-engine'
-
-export async function GET(request: NextRequest): Promise<NextResponse> {
-  const cronSecret = request.headers.get('x-cron-secret')
-
-  if (!cronSecret || cronSecret !== process.env.CRON_SECRET) {
-    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
-  }
-
-  try {
-    const now = new Date()
-    const results: Array<{ roundId: string; action: string; success: boolean; errors?: string[] }> = []
-
-    // Find a SUPER_ADMIN to use as the actor for audit logging
-    const systemActor = await prisma.user.findFirst({
-      where: { role: 'SUPER_ADMIN' },
-      select: { id: true },
-    })
-
-    if (!systemActor) {
-      return NextResponse.json({
-        ok: false,
-        error: 'No SUPER_ADMIN user found for system actions',
-      }, { status: 500 })
-    }
-
-    // 1. Activate DRAFT rounds whose windowOpenAt has arrived
-    const roundsToOpen = await prisma.round.findMany({
-      where: {
-        status: 'ROUND_DRAFT',
-        windowOpenAt: { lte: now },
-        competition: { status: { not: 'ARCHIVED' } },
-      },
-      select: { id: true, name: true },
-    })
-
-    for (const round of roundsToOpen) {
-      const result = await activateRound(round.id, systemActor.id, prisma)
-      results.push({
-        roundId: round.id,
-        action: `activate: ${round.name}`,
-        success: result.success,
-        errors: result.errors,
-      })
-    }
-
-    // 2. Close ACTIVE rounds whose windowCloseAt has passed
-    const roundsToClose = await prisma.round.findMany({
-      where: {
-        status: 'ROUND_ACTIVE',
-        windowCloseAt: { lte: now },
-      },
-      select: { id: true, name: true },
-    })
-
-    for (const round of roundsToClose) {
-      const result = await closeRound(round.id, systemActor.id, prisma)
-      results.push({
-        roundId: round.id,
-        action: `close: ${round.name}`,
-        success: result.success,
-        errors: result.errors,
-      })
-    }
-
-    return NextResponse.json({
-      ok: true,
-      processed: results.length,
-      results,
-      timestamp: now.toISOString(),
-    })
-  } catch (error) {
-    console.error('Cron round-scheduler failed:', error)
-    return NextResponse.json(
-      { error: 'Internal server error' },
-      { status: 500 }
-    )
-  }
-}