fix(explorer): make console account tables and header responsive

> [!IMPORTANT]
> Current execution is tracked by #436. This issue owns responsive console account tables and header behavior in PR #420, after #398 / PR #419. Subsequent Squid fee budgeting begins at #437 / PR #421. Historical references below are retained for attribution.

Parent tracker: #393
Independent base: staging

## Goal

Make the console header, wallet controls, and account data tables usable at a 390 px viewport without clipping or hiding required actions.

## Scope

- Responsive header/navigation behavior.
- Responsive wallet control layout.
- Account table overflow or compact presentation using existing UI primitives.
- Focus and keyboard behavior at desktop and mobile widths.

## Non-goals

- Button/theme redesign.
- Landing-page redesign.
- Funding or authentication behavior changes.

## Acceptance criteria

- [ ] The relevant pages fit at 390 px without horizontal page clipping.
- [ ] Wide tabular data remains accessible without removing fields.
- [ ] Wallet, navigation, and row actions remain keyboard reachable.
- [ ] Component tests cover the responsive structure where meaningful.
- [ ] Desktop layout is unchanged outside the intended responsive rules.
- [ ] Repository-required checks pass and screenshots are attached for mobile and desktop.

Performance classification: not performance-relevant.

Start with the current execution tracked by #436 and the responsive work in PR #420, using the scope and acceptance criteria here as the checklist. Verify the 390 px and desktop behavior, keyboard reachability, component coverage, required checks, and requested screenshots before considering the work done.

Written by the indexing model from the issue text.