### What happened

`omarchy install service sunshine` aborts on a fresh install:

```
Installing Sunshine...
Failed to enable unit: Unit sunshine.service does not exist
```

The installer runs `systemctl --user enable --now sunshine`, but the `sunshine`
package ships its unit as `app-dev.lizardbyte.app.Sunshine.service`, with
`sunshine.service` only as an `[Install] Alias=`. A unit alias does not exist
until the real unit has been enabled at least once, so enabling it by the short
name fails.

Because `omarchy-install-service-sunshine` runs under `set -e`, the abort skips
every remaining step: the UFW rules, the Sunshine Admin web app, and the
Hyprland autostart entry. Sunshine ends up installed but unconfigured, and the
user gets no indication that the firewall was never opened.

### The failure is symmetric

Working around it by enabling the real unit does not make the installer
succeed. Enabling `app-dev.lizardbyte.app.Sunshine.service` causes systemd to
create the alias as a symlink in `~/.config/systemd/user/`, and a re-run then
fails differently:

```
Installing Sunshine...
Failed to enable unit: Refusing to operate on linked unit file sunshine.service
```

So the installer fails before the unit is enabled, and fails after it is
enabled. There is no state in which that line succeeds.

### Expected

The installer enables and starts Sunshine, then continues to the firewall,
web app, and autostart steps.

### Steps to reproduce

1. On a system with no prior Sunshine install, run `omarchy install service sunshine`.
2. The run aborts at the enable step.
3. Run `systemctl --user enable --now app-dev.lizardbyte.app.Sunshine.service`.
4. Re-run `omarchy install service sunshine`; it now aborts with "Refusing to
   operate on linked unit file".

### Suggested fix

Enable the unit by its real name in `omarchy-install-service-sunshine`:

```bash
systemctl --user enable --now app-dev.lizardbyte.app.Sunshine.service
```

Guarding the call so an already-enabled unit does not abort the rest of the
script would also stop a single failure from silently skipping the firewall
rules.

### Unrelated note on the same installer

On this machine the default capture path produced no working hardware encoder
and Sunshine fell back to `libx264`, on a 4K display with an RTX 5070. NVENC
tested fine outside Sunshine. Setting `capture = kms` in `sunshine.conf` made
`h264_nvenc`, `hevc_nvenc`, and `av1_nvenc` all available. The display uses a
1.5 fractional scale, which may be the trigger. Mentioning it only in case the
installer should ship a capture default; happy to open a separate issue.

### System

| | |
|---|---|
| Omarchy | 4.0.3-1 |
| sunshine | 2026.516.143833-4.1 |
| Hyprland | 0.56.2 |
| Kernel | 7.2.3-arch1-3 |
| CPU | AMD Ryzen 7 7700 |
| GPU | NVIDIA RTX 5070 (nvidia-open-dkms 610.57.04) + AMD Raphael iGPU |