[pikann]

Summary

Adds the AppPageProps type for the new app.page extension point, so plugins can register a full-bleed, top-level page that no sidebar lists.

• src/extension-points.ts: new AppPageProps extends BaseExtensionProps, added to the ExtensionPointProps union and to the extension point list in the header comment.
• src/index.ts: exports AppPageProps.

Why

A plugin sometimes needs its own URL on the Paca origin. The usual case is the address an external service redirects the browser back to, such as an App-installation or OAuth callback. app.page renders at /plugin-pages/:pluginId/:slug (nav item scope: "app").

Behavior notes (documented in the type's JSDoc)

• The page sits under the host's authenticated layout. By the time it mounts, an expired access token has been refreshed, or the user has signed in and been returned to the page.
• The injected api client calls the plugin's own backend as that user. It has no projectId (global scope).
• The callback's query string should be read from window.location and treated as untrusted input.

Notes

• Type-only change with no runtime impact. AppPageProps adds no props beyond BaseExtensionProps, like AdminPageProps.
• Pairs with the host-side app.page extension point support in the Paca app.