feat(web): wire dashboard page to display authenticated user info from /api/v1/me

[GRACENOBLE]

Problem

The dashboard page is empty. Fetching and displaying the current user's profile is the most natural first example of an authenticated API call from the web layer.

Acceptance criteria

• Dashboard page fetches /api/v1/me (via a Server Component or tRPC query)
• Display at minimum: display name, email, and account creation date
• Show a skeleton/loading state while the request is in flight
• Show an error state if the request fails
• Add a Vitest component test

[GRACENOBLE]

Implemented and merged via PR #67.