:unread_badge — add aria_label for accessibility

Canonical-grep proof

$ git grep -n "kind: :unread_badge" packages/live_ui/lib/live_ui/renderer.ex
packages/live_ui/lib/live_ui/renderer.ex:<line>:  def render(%{element: %Element{kind: :unread_badge}} = ...)

Renderer clause exists (PR #179); constructor accepts count + threshold opt — but NO aria_label for screen-reader accessibility.

Divergence (ariston consumer vs canonical)

Ariston's operator-surface unread-badge usage (ariston-ui/lib/ariston_ui_web/live/operator_surface_live.ex:930-941) passes a per-instance aria_label:

Proposed extension

Add an optional aria_label attr:

@spec unread_badge(non_neg_integer(), opts()) :: Element.t()
def unread_badge(count, opts \\ [])
# Existing opts: threshold, id
# NEW opt: aria_label (string; if provided, emit on the rendered span)

In the renderer clauses (live_ui + ash_ui): when aria_label is provided, emit aria-label={value} on the badge's root element. When not provided: existing behavior (badge has implicit semantics via count text + role="status").

Note on what's NOT proposed

The "loud" ariston attr (unread > 5 historical visual variant) is being dropped from ariston-side. Canonical's threshold-capping is sufficient; ariston can re-emit "loud" visual treatment via CSS rule against the canonical badge's data-live-ui-unread-count attr if desired.

Status

This is a small a11y fix. Once landed, ariston PR #351 restores screen-reader-friendly labels on unread badges.

Cross-references

• Authoring PR: unified_ui#179 (merged 101bae98)
• ash_ui sync: The-Metagraph/ash_ui#108 (merged a32fb5519fb9)
• ariston-ui consumer site: lib/ariston_ui_web/live/operator_surface_live.ex:930-941
• Audit protocol: docs/audit-protocols/canonical-grep-required.md

Sibling issues this batch:

• :top_strip event-wiring attrs
• :sidebar_item visual+state primitives