### What happens

A custom `type: "command"` bar module cannot render as empty. When the script prints Waybar-style JSON with an empty `text`, the bar displays **the raw JSON string** instead of nothing:

```
{"text":"","tooltip":"","class":"idle"}
```

This makes the documented "print JSON" contract unusable for any widget that should be conditionally visible — a printer queue, a VPN indicator, an update counter. Anything that is idle most of the time.

### Why

`CustomCommandModule.update()` in `shell/plugins/bar/Bar.qml` uses `||` to fall back, so an empty string (falsy in JS) takes the fallback branch:

```qml
// Bar.qml:1799 (main)
outputText = data.text || String(raw || "").trim()
```

With `data.text === ""` the expression falls through to `raw` — the entire JSON line — and that is what gets rendered.

The same falsy pattern repeats one binding later:

```qml
// Bar.qml:1805 (main)
text: outputText || String(setting("text", ""))
```

The irony is that the hide mechanism already exists and works correctly — it is just unreachable through JSON:

```qml
// Ui/WidgetButton.qml
property bool hasVisualContent: text !== ""
visible: hasVisualContent || keepSpace
```

A module that emits **no output at all** does reach it: `Util.parseModuleJson("")` returns `{}`, `outputText` stays `""`, and the widget correctly disappears. So the empty state is reachable by printing nothing, but not by the documented JSON contract.

### Expected

`{"text":""}` hides the widget, exactly as empty output does. An explicitly empty `text` is a value, not an absent one, and should not be replaced by the raw line.

### Steps to reproduce

1. Create `~/.config/omarchy/bar/scripts/demo`:

   ```bash
   #!/usr/bin/env bash
   echo '{"text":"","tooltip":"","class":"idle"}'
   ```

   ```bash
   chmod +x ~/.config/omarchy/bar/scripts/demo
   ```

2. Add it to `bar.layout.right` in `~/.config/omarchy/shell.json`:

   ```json
   { "id": "demo", "type": "command", "exec": "~/.config/omarchy/bar/scripts/demo", "interval": 3 }
   ```

3. Save. The bar shows the literal text `{"text":"","tooltip":"","class":"idle"}`.

Changing the script to print nothing instead makes the widget correctly invisible, which isolates the fallback as the cause.

### Suggested fix

Distinguish absent from empty:

```qml
outputText = data.text !== undefined ? String(data.text) : String(raw || "").trim()
```

and correspondingly for the `text:` binding, so an explicit `""` is honoured while a missing key still falls back.

### Workaround

Emit no output at all in the idle state rather than JSON with an empty `text`.

### System details

| | |
|---|---|
| Omarchy | 4.0.2-1 |
| Kernel | 7.1.9-arch1-2 |
| Hyprland | 0.56.2 |
| CPU | Intel Core i5-4670K (Haswell) |
| GPU | NVIDIA GA106 [GeForce RTX 3060], nvidia 610.57.04 |
| Machine | ASUS H87-PRO, desktop |

Verified against `main` (`shell/plugins/bar/Bar.qml` lines 1799 and 1805 at time of filing), not just the packaged 4.0.2 copy.

### Note

While reproducing this I also hit the `moduleName` read-only TypeError, which is already tracked in #9701 with a fix in #9972. This report is a separate defect in the same component: #9701 is log noise, this one is visible wrong output.