### What happened

`omarchy-launch-screensaver` decides whether a screensaver is already running with:

```bash
# Exit early if screensaver is already running
pgrep -f '[o]rg.omarchy.screensaver' && exit 0
```

`pgrep -f` matches against the **full command line of every process on the system**, not
just screensaver terminals. So any unrelated process whose command line happens to contain
the string `org.omarchy.screensaver` satisfies this check, and the launcher exits early.

The failure is silent and reports success: **exit code 0, no output, no notification, and
no screensaver.** Every other early-exit path in the script (`ttfx` missing, the
`screensaver-off` toggle, an unsupported terminal) exits 1, and the unsupported-terminal
case at least sends a notification. This one is indistinguishable from a normal successful
launch.

It affects the idle path as well as manual invocation. `omarchy-shell` runs the launcher and
logs only the exit code, so the log shows what looks like a healthy cycle:

```
DEBUG qml: omarchy idle ... process-start: screensaver [[ $(omarchy-shell lock isLocked 2>/dev/null) == "true" ]] || omarchy-launch-screensaver
DEBUG qml: omarchy idle ... process-exit: screensaver exitCode=0 status=0
```

### What I expected

The screensaver to launch, or failing that, to fail visibly rather than report success.

### Steps to reproduce

```bash
# 1. Confirm no screensaver is running
pgrep -f '[o]rg.omarchy.screensaver'; echo "exit=$?"     # -> exit=1

# 2. Start any unrelated process whose command line contains the class string.
#    (Nothing here touches the screensaver; $0 is simply set to that string.)
sh -c 'sleep 120' org.omarchy.screensaver &

# 3. Ask for the screensaver
omarchy-launch-screensaver force; echo "exit=$?"
#    -> prints the PID of the sleep, exits 0, and no screensaver appears
```

This is not contrived. I hit it while diagnosing an unrelated screensaver question: a
command containing `select(.class=="org.omarchy.screensaver")` was enough to suppress the
screensaver on the next invocation, with no indication why.

### Suggested fix

Test the actual condition (is a screensaver window mapped) rather than a string in an
arbitrary command line. The script already calls `hyprctl ... -j | jq` a few lines further
down, so this adds no dependency:

```bash
# current
pgrep -f '[o]rg.omarchy.screensaver' && exit 0

# proposed
hyprctl clients -j | jq -e 'any(.[]; .class == "org.omarchy.screensaver")' >/dev/null && exit 0
```

Happy to open a PR for this if the approach looks right.

### System details

- Omarchy 4.0.2-1
- Hyprland 0.56.2
- hypridle 0.1.8-1, foot 1.27.0-2, ttfx 0.3.2-1, procps-ng 4.0.7-1
- AMD Ryzen 5 7600X, Radeon RX 9070 XT (Navi 48)
- Single monitor, terminal is foot