Describe the bug

The plugin subsystem resolves its storage directory with ProjectDirs::from("com", "debba", "tabularis") (src-tauri/src/plugins/installer.rs, manager.rs), while the rest of the application — config, themes, AI activity, heartbeat — uses ProjectDirs::from("", "", "tabularis") (src-tauri/src/paths.rs), and the Tauri bundle identifier is tabularis.

Because of the extra qualifier/organization, plugins are installed and loaded from a different folder than every other piece of app data:

This also contradicts the documentation (plugins/PLUGIN_GUIDE.md, plugins/README.md, plugins/PLUGIN_TUTORIAL.md) and the scaffolder template (packages/create-plugin/templates/rust-driver/justfile.tmpl), which all declare the plugins folder under tabularis (e.g. %APPDATA%\tabularis\plugins\). A plugin placed at the documented path — or dev-installed via just dev-install — is therefore not discovered by the loader on macOS and Windows.

Expected: all app data, including plugins, lives under a single tabularis directory on every platform, matching the documentation.

To Reproduce

1. On macOS or Windows, install a plugin from Settings → Plugins (or scaffold one with @tabularis/create-plugin and run just dev-install).
2. Look inside the documented app data folder — macOS: ~/Library/Application Support/tabularis/plugins/.
3. The plugin is not there: it landed in ~/Library/Application Support/com.debba.tabularis/plugins/ instead, split from the rest of the app data and not matching the docs.

OS Version

macOS 14.x (also affects Windows; Linux unaffected)

Tabularis Version

v0.12.0

Relevant Log Output

(no error logged — plugins silently load from / save to the wrong directory)