Early warning alert before VW PQ 6-minute steering limit

### Describe the bug or enhancement

Unfortunately, my car is an older Volkswagen with an APA-BS steering rack that hasn't been hacked yet, so the 6-minute timer still disrupts my drive. While openpilot manages both lateral and longitudinal control, the car issues visual and audio alerts the moment it hits the time limit—simultaneously slowing down and cutting power steering. After reviewing the documentation and codebase with AI assistance, I believe the best balance of safety and convenience is to trigger warning alerts 5 to 6 seconds before the limit. This gives the driver enough time to take over or make a manual steering input to reset the timer.

### Provide a route where the issue occurs if applicable

_No response_

### openpilot version if applicable

0.11.1

### Additional info

_No response_

No file, test, or route is named. Start by locating the Volkswagen PQ steering-limit timer and the code that emits its visual and audio alerts, then determine how the 6-minute limit is represented. Done means warning alerts occur 5–6 seconds before the limit while the existing takeover and manual steering behavior remains safe.

Written by the indexing model from the issue text.