[rd-code-23]

Problem

The protected dashboard only displayed a generic page heading. New registered users and guests need an intentional introduction that acknowledges how they entered the application without duplicating authentication logic.

What changed

• Replaced the generic dashboard heading with an identity-aware introduction.
• Guests see Welcome, Guest.
• Registered users see their display name, falling back to their email when no display name exists.
• Added the onboarding message Let's get stronger today.
• Made the identity already resolved by the protected application layout available to nested route pages through a narrowly scoped React context.
• Added focused tests for guest and registered-user wording and updated affected integration assertions.

How it works

The access boundary remains the single place that resolves whether the visitor is a guest or registered user. The protected _app layout places that resolved identity into ApplicationIdentityContext around the application shell and TanStack Router outlet. The dashboard page reads the same value, so it does not issue another current-user request or repeat guest-session detection.

Context is appropriate here because ApplicationShell is rendered directly and can receive an identity prop, while DashboardLanding is selected indirectly by TanStack Router inside <Outlet />. The context carries the existing identity across that nested route boundary; it does not create a second identity source or act as a general global store.

The identity module also provides useApplicationIdentity, which centralizes the missing-provider check and gives consumers a non-null, descriptive API. This avoids unsafe assertions and repeated context validation.

Scope

This is the first mini-task under #40. It includes only the dashboard introduction and identity delivery needed by that introduction. Weekly activity, scheduled-workout, routines, and workout-history empty states remain separate follow-up tasks.

Testing

• Added direct coverage for guest and registered-user greetings.
• Updated the welcome-to-guest-dashboard and application-shell integration expectations.
• Verified all 21 web tests pass.
• Verified web type-checking, ESLint, changed-file formatting, and diff checks.