…WCAG 1.4.1)

Adds aria-label to the SVG <g role="button"> wrapper on each
timeline-graph node so screen readers announce the workflow id
and status (or event type and classification) instead of bare
"button".

Previously, terminal statuses on the timeline graph (Completed,
Failed, Canceled, TimedOut, Fired, Signaled) were distinguishable
only by node color. The color legend lives inside a Tooltip --
keyboard- and AT-reachable since PR #3429, but still requires the
user to leave the graph, decode the color, and come back to
identify each node. This change makes the graph self-describing.

Cross-cutting wins:
- Closes the SC 4.1.2 missing-accessible-name defect on the same
  <g role="button"> widgets.
- Closes the SC 1.3.1 matrix-row item d deferred to the Robust
  wave.

New i18n keys:
- workflows.row-accessible-name = "Workflow {{workflowId}}: {{status}}"
- events.row-accessible-name = "Event {{eventType}}: {{classification}}"

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CI's check-types caught two TS errors in the timeline-graph
aria-label additions:

1. translate(\`workflows.\${workflowStatusKey(status)}\`) -- the
   helper's return type widened to plain string, which doesn't
   satisfy the strongly-typed translation-key union.
2. translate(\`events.event-classification.\${classification.toLowerCase()}\`)
   -- same shape; toLowerCase() returns plain string.
3. event.eventType -- doesn't exist on PendingActivity (a union
   member of WorkflowEventWithPending).

Replaced both dynamic template-literal lookups with `as const`
record literals keyed by the literal-union enum values, so
TypeScript can narrow to the exact translation-key union. Added
an `in` operator narrowing for the eventType access.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

EventClassification union doesn't include 'Retrying' -- only the
i18n key exists. The lookup entry was unreachable.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Previously the aria-label for a pending activity always said
"Pending" regardless of attempt count. The timeline already
communicates retry state visually (line styling), in the legend
("Retry" entry), and in the group-details row text -- but the
per-event aria-label missed it.

Check group.pendingActivity.attempt > 1 (matching the existing
group-details-row.svelte logic) and surface "Retrying" in the
aria-label when applicable. The events.event-classification.retrying
translation key already existed for this purpose.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

The status/classification -> translated-label mapping existed inline in
workflow-status.svelte and was duplicated by the two new lookup tables
added for the timeline-graph aria-labels (workflow-row,
history-graph-row-visual). Extract the canonical map into
$lib/utilities/get-status-label and reuse it in all three call sites so
there is a single source of truth.

No behavior change: the helper map is a verbatim copy of the canonical
Record<Status, string>; the history graph normalizes its lowercase
'pending'/'retrying' values to the PascalCase Status union for lookup
while leaving `classification` untouched for styling.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>