## Summary

Omarchy 4.0.4 (upgraded from 4.0.2) breaks third-party plugins that ship
helper binaries or bundled data files: the sanitized manifest handed to the
plugin no longer contains `__sourceDir`, and no injected API exposes the
plugin's own source directory as a replacement.

## Evidence

In 4.0.2, plugin instances received the raw manifest:

```qml
if ("manifest" in target) target.manifest = manifest
```

In 4.0.4, `publicPluginManifest()` sanitizes it for third-party plugins and
deletes `__sourceDir`:

```qml
function publicPluginManifest(manifest) {
    if (!manifest) return null
    if (manifest.__isFirstParty) return manifest
    var copy = JSON.parse(JSON.stringify(manifest))
    delete copy.__sourceDir
    delete copy.__isFirstParty
    delete copy.__hostCapabilities
    return copy
}
```

`__sourceDir` is the plugin's own directory — it is not host-internal state
like `__isFirstParty` or `__hostCapabilities`. First-party plugins still
receive it and need it; third-party plugins now have no way at all to resolve
their own files.

## Real-world breakage

QOpen (https://github.com/CoderLambert/qopen-omarchy-plugin) resolved its
backend this way since v2.3.0:

```qml
readonly property string pluginDir: (manifest && manifest.__sourceDir) || ""
readonly property string backendPath: pluginDir ? pluginDir + "/bin/qopen" : ""
```

After the 4.0.4 upgrade the launcher opens with "0 resources" and no error:
`pluginDir` is empty, so the catalog request never fires and the UI silently
shows an empty list while `~/.config/qopen/config.json` is fully intact.

## Suggested fix

Keep `__sourceDir` on the manifest handed to third-party plugins (it is the
plugin's own path, not a host secret), or expose the plugin's source directory
through a dedicated property on `PluginShellApi` / `PluginRegistryApi`.

As a stopgap, QOpen now recovers the directory by parsing its own entry point
URL from `pluginRegistry.entryPointUrl(manifest, "menu")` — workable, but an
API contract should not force plugins to parse URLs to find their own files.