### Omarchy version
3.8.4

### Hardware
Dell laptop with `dell::kbd_backlight` (max brightness 2)

### Summary
After idle lock/unlock, the keyboard backlight stays off until the physical backlight key is pressed. Software restore does not bring it back, and typing does not re-enable it either.

### Expected
`omarchy-system-wake` restores the previous non-zero keyboard backlight level.

### Actual
Backlight stays at 0 after unlock. Only the hardware backlight key restores it.

### Root cause
Dell exposes an idle timeout via sysfs:

- `/sys/class/leds/dell::kbd_backlight/stop_timeout` (default `1m`)
- After ~1 minute idle, brightness is already `0`

Lock path in `omarchy-system-lock` (when not `OMARCHY_LOCK_ONLY`) does:

```bash
omarchy-brightness-keyboard off   # brightnessctl -s set 0
```

`omarchy-brightness-keyboard off` is effectively:

```bash
brightnessctl -sd "$device" set 0
```

That **saves the current value, then sets 0**. By lock time (~2.5 min via hypridle), current is already **0** from `stop_timeout`, so the saved state is **0**.

Wake then runs:

```bash
omarchy-brightness-keyboard restore   # brightnessctl -r
```

which restores **0**. Explicit software `set 0` also tends to leave Dell in a full “off” mode where activity / `start_triggers` no longer revive the light until the physical key is used.

### Repro
1. Set keyboard backlight to a non-zero level
2. Idle until hypridle locks (or lock via system lock)
3. Unlock
4. Keyboard backlight remains off

### Confirmed on system
- Save file can contain `0`: `/run/user/$UID/brightnessctl/leds/dell::kbd_backlight`
- `stop_timeout=1m`, `start_triggers=+keyboard +touchpad`
- Related scripts: `omarchy-brightness-keyboard`, `omarchy-system-lock`, `omarchy-system-wake`

### Suggested fix
In `omarchy-brightness-keyboard` (and/or lock/wake):

1. Persist **last non-zero** level in a state file
2. On `off`: save only if current > 0; never overwrite state with 0
3. On `restore`: apply last non-zero level (fallback to a sane default, e.g. mid step)
4. Optionally snapshot level on idle *before* `stop_timeout` (e.g. ~30s)

Happy to test a PR on Dell hardware.