feat(hosted-web): add blank app path to Add app

[The-AarushiSingh]

Summary

Add app was catalog-only, and "Connect a service" requires an MCP URL, so there was no way to create an empty app from the dashboard without going through an agent (reported in Discord).

This adds a Create blank app button next to "Connect a service". It asks for a name only, reads the host's release from framework.release, and calls the existing apps.deploy with index.ts and a package.json that pins dependencies.apps to that release (the build rejects apps without the pin). On success it opens the app's Source view, since a blank app has nothing to show on Overview.

Deploying through the existing endpoint keeps this on the same path as catalog installs, so there are no server changes. Catalog install and MCP import are untouched.

Scope

Hosted only (cloud and self-host share this page). The local app has its own bindings and isn't included; happy to follow up if you want parity.

Testing

• Ran the flow on a self-host build from this branch (Docker, Linux): Create blank app → name → lands on Source with index.ts and package.json.
• tsc --noEmit on apps/hosted/web and apps/local/web; oxlint and oxfmt on the changed files.
• Not run: bun run typecheck and the e2e suite (I develop on Windows, where tsc-rs has no binary).

The Add app page with Create blank app next to Connect a service

The Source view of the new app