feat(a11y): implement ARIA tablist pattern across all tab strips (#1031)

[ceotjoe]

Summary

• Adds shared src/utils/ariaTabKeyDown.js utility for W3C APG arrow-key / Home / End navigation
• Converts all 7 tab-strip components to the full ARIA tablist pattern: role="tablist", role="tab" + aria-selected + aria-controls, roving tabIndex, role="tabpanel" + aria-labelledby
• Removes aria-pressed from MeshComPanel (wrong pattern for tabs)

Components updated: SettingsPanel (9 tabs), MeshComPanel, PotaSotaPanel, DXFilterManager, ActivateFilterManager, PSKFilterManager, PSKReporterPanel

Test plan

• Open Settings panel — screen reader announces "Settings tabs" tablist, each tab announces as selected/not selected, arrow keys move between tabs
• MeshCom panel — same pattern, no more aria-pressed
• POTA/SOTA panel — arrow keys navigate between POTA/WWFF/SOTA/WWBOTA
• DX Filter, Activate Filter, PSK Filter modals — tablist navigation works
• PSKReporter tx/rx sub-tabs — tablist with arrow keys
• Visual styling unchanged across all components

Closes #1031

🤖 Generated with Claude Code

[accius]

Nice cleanup of the tablist pattern across all seven tab strips. The shared ariaTabKeyDown helper is exactly the kind of utility that should exist for this — arrow / Home / End wrapped behavior in one place, components just pass their tab-id array and the active state setter.

A few things I liked:

The roving tabIndex (0 on active, -1 on others) is the W3C APG pattern and means tab key skips the inactive tabs entirely — keyboard users don't have to step through every tab to leave the strip. The ref callback that populates tabRefs.current and the setActiveTab + .focus() move on arrow press completes the loop.

Dropping aria-pressed from MeshComPanel is correct — aria-pressed is the toggle-button pattern and was lying about what those tabs were. Replacing it with aria-selected + role="tab" is the right semantic.

MeshComPanel switching from conditional mount to hidden/display:none panels is the only non-trivial behavior change. It means all three tab subtrees stay mounted, which has a small memory cost but matches APG and gives screen readers stable aria-controls targets. I think that's the right tradeoff here — those panels are cheap.

PSKReporter only wires the tablist for the PSK panel mode (not for the wsjt/Decodes/QSOs mode) — that's a deliberate scope decision and reasonable. Worth a followup later but not blocking.

Good to merge.

K0CJH