Next.js v16.2.0-canary.67: Test Mode Refinements v16.2.0-canary.67

Next.js 16.2.0-canary.67 just shipped with a focused fix on test mode execution with custom deploy scripts. We've tightened up when main test mode actually runs, so your CI/CD doesn't go rogue. Shoutout to @ijjk for the assist. Canary channel, lowkey solid.