Kaia Counter Test v0.5.9 — 12-hour final

Source:
- Created by copying v0.5.7.
- v0.5.7 remains untouched.

Fix:
- Preserve "One number is issued per donation." in the locked/reloaded display.
- The reloaded number remains masked as KaiaSpec.
- Issuance/cooldown/history behavior is unchanged.

Validation:
- PHP syntax check passed.


Final change:
- Cooldown/lock period is fixed at 12 hours (720 minutes).
- Fresh installs default to 720 minutes.
- Existing v0.5.8 installations are migrated once to 720 minutes.
