run_app now keeps and serves what every app's panel and page need, with the same caller checks
as the rest (commands::SHELL: shell_only first; testkit::assert_host_guards covers them):
- app.rs: PageState (the plugin store in app data `plugins`, the feature flags, ShellSettings)
managed by the host; commands plugins_list, plugin_set_enabled, plugins_open_folder,
custom_css_get/set, features_get/set, settings_get/set (moved from wayBetter for X). The app
reads the state through app::page(), gets a loaded document's scripts from app::page_scripts()
(flags, links, custom CSS, plugins) and writes through set_features/set_settings/set_custom_css
(a backup import). AppConfig takes the app's PluginHost (AppConfig::new(site, title, plugins))
and an optional home_url. SiteHooks::navigation_started and new_window_mode default to the
owner's link settings.
- settings.rs (pure, tested): ShellSettings { homeUrl, externalLinks, siteLinks, restoreTabs }
with its input form (missing fields take the defaults; `xLinks`, the name wayBetter for X used,
is read as siteLinks), links_script ({ site: mode }), feature validation and features_script.
- commands::SITE + open_panel: a tab on the site's origin asks the shell to open the app's panel
(site_tab_only first). testkit: assert_site_only(command, site) checks that every capability
granting a site command is a tab capability limited to the site's URLs; assert_host_commands and
assert_host_guards include the site commands.
- shell frame backupModel: a settings section that still says xLinks compares as siteLinks.
The `app` feature (App / run_app, AppConfig, SiteHooks): registers the Tauri plugins every app
uses (single-instance, deep-link and updater opt-in, window-state, opener, process, notification,
dialog), makes app data, loads profiles and the language, builds the window (restore, lost-geometry
reset, helper-close routing, native resize follow) and the transparent shell, and serves tabs_sync,
tab_navigate, tab_action, open_external_url, shell_focus, shell_raise, window_system_menu,
profiles_get/set, i18n_get/set (shell-only) and tab_shortcut, tab_link_drag (tab-only). The tab
builder is generic; the app fills in SiteHooks. `commands` lists them (manifest() for build.rs),
`testkit` checks capability files and caller guards, i18n::page_script is origin-guarded.
check:tauri now checks the app feature.
