Gotta Go Trophy Unlocks Early

## Description
Starting from blank NVS, when you play fewer than 20 rounds the `T_ROUNDS_20` achievement unlocks.

## Expected behavior
The achievement should wait until 20 rounds are actually played.

## Reproduction Steps
Wipe NVS and play timed mode

## Screenshots
n/a

## Logs
n/a

## Affected Version
- Platform: Linux, at least
- git branch: `main`
- git hash: 3dcd3fd203aea2aaf9b39fb24ff86a8e3de967c5

## Additional Notes
n/a

Search for `T_ROUNDS_20` and locate where timed-mode round count is incremented and checked for achievement unlock. Follow the startup/reset path for blank NVS so you can verify how the counter is initialized before gameplay begins. Reproduce with a clean NVS on the `main` branch and timed mode, then confirm the trophy stays locked before 20 rounds and unlocks at exactly 20.

Vom Indexierungsmodell aus dem Issue-Text verfasst.