Faster Legal Center: compressed assets and a11y polish

The Legal Center got the same compression and deferral treatment the admin app already had:

• Static assets compress at build time, so CSS and font payloads shrink.
• Third-party scripts defer until after first interaction.
• The project logo is now served at the right resolution per breakpoint instead of one oversized version everywhere.

We also resolved a batch of accessibility audit findings while we were in there — colour contrast on muted text, missing focus styles on the navigation, and a couple of aria-current attributes that were not being set on active nav items. Accessibility scores are now consistently in the 90s across the Legal Center surfaces.