## What happened

For a third-party plugin whose manifest started as `"kinds": ["overlay"]`
and later gained `"bar-widget"` (new `entryPoints.barWidget` +
`barWidget` block, e.g. after adding a status-bar icon to an existing
overlay plugin), both `omarchy plugin enable <id>` and the underlying
`omarchy-shell shell putBarWidget <id> '{}'` IPC call report success but
do nothing: the widget is never added to `shell.json`'s `bar.layout`, and
`omarchy plugin list` keeps reporting it as disabled.

## Root cause

In `shell/services/PluginRegistry.qml`, `setEnabled()` computes
`location = findEntryLocation(config, key)` up front. Because the plugin
already has a top-level entry in `config.plugins[]` (added back when it
was still overlay-only), `location.found` is `true`. The bar-widget
insertion branch is guarded by:

```js
if (!location.found && isBarWidget) {
  ... config.bar.layout[target.section].splice(target.index, 0, entry) ...
}
```

so it's skipped — the plugin is treated as "already enabled" and nothing
is written to `bar.layout`.

But `shell.qml`'s `listPlugins()` defines `enabled` for anything with
`bar-widget` in `kinds` as `shell.pluginRegistry.inBar(id)` (checks
`bar.layout` specifically, not `plugins[]`):

```js
enabled: isBarOption ? active
  : (isBarWidget ? shell.pluginRegistry.inBar(id) : shell.pluginRegistry.isEnabled(id)),
```

So the two functions disagree about what "enabled" means for this
plugin, and there is no way to get the widget placed via the documented
`omarchy plugin enable` / `putBarWidget` path once this state is reached.

`putBarWidget()` hits the same wall: it only special-cases `inBar(id)`
before delegating straight to `setEnabled(id, true, target)`, so it fails
identically once `location.found` is already true for another reason.

## Repro

1. Install/enable a plugin with `"kinds": ["overlay"]` only. This adds
   `{ "id": "<id>" }` to `shell.json`'s top-level `plugins[]`.
2. Update the plugin's `manifest.json`: add `"bar-widget"` to `kinds`,
   plus `entryPoints.barWidget` and a `barWidget` block pointing at a new
   QML file.
3. `omarchy-shell shell rescanPlugins`
4. `omarchy plugin enable <id>` → prints "Enabled `<id>`", exit 0. (Or:
   `omarchy-shell shell putBarWidget <id> '{}'` → returns `"ok"`.)
5. `omarchy plugin list --json` still shows `"enabled": false` for
   `<id>`, and `shell.json`'s `bar.layout` has no entry for it.

## Expected

Step 4 should add the widget to `bar.layout` (at the plugin's
`barWidget.defaultSection`, same placement a brand-new install would
get), matching what `listPlugins()` actually checks for a
bar-widget-kind plugin's `enabled` state.

## Workaround

Manually add `{ "id": "<id>" }` to the right `bar.layout.<section>`
array in `shell.json` by hand; the running shell picks it up live and
`omarchy plugin list` then correctly reports it enabled.

## System

- Omarchy 4.0.2-1
- Hyprland 0.56.2
- omarchy-shell / Quickshell — live process, IPC responsive throughout