feat(wallet): add data-journey-state to MainWalletPage with tests

[rxiddhi]

What does this PR do?

This PR adds a derived data-journey-state attribute to the main wallet container in MainWalletPage.

It also:

• extracts the journey-state derivation into a small pure helper
• derives the state from existing wallet and service signals only
• adds unit tests for the derivation logic
• adds React Testing Library coverage for the rendered attribute
• adds an explicit precedence test to ensure service-offline wins over no-wallet

This is an additive UI-only change intended to make follow-up state-aware guidance work easier to implement and test. It does not change backend behavior or existing wallet flows.

Motivation / Context

Jam already has the wallet and service state needed to identify common first-run situations, but that state is not currently surfaced in one predictable place on the main wallet route.

Exposing a deterministic journey-state marker is a small, low-risk step toward better onboarding and contextual wallet guidance.

Dependencies

• No backend or API changes
• No new dependencies

Risk

Low. This change only adds a DOM attribute and pure derivation logic, with unit and RTL coverage.

Visual Demo (For contributors especially)

Image Demo

The screenshot below shows the main wallet page with Chrome DevTools open and the main wallet container selected in the Elements panel.

The selected node renders:

• data-journey-state="empty-wallet"

This demonstrates that the derived journey state is present in the DOM and available for follow-up guidance work, even though this PR does not introduce a visible UI change yet.