feat: deployment dashboard

[starkiVector-090]

Added tests for the three previously untested components:

• AnalyticsCard.test.tsx — 8 tests: label/value rendering, subValue, positive/negative
  trend badges, no-trend case, accessible article role, id attribute
• AnalyticsGrid.test.tsx — 8 tests: all six cards present, value formatting (total,
  success rate, duration in m/s and s-only), accessible section role, failure sub-value
  variants
• DeploymentRow.test.tsx — 15 tests: name/commit/status/environment rendering, duration
  formatting, visit link presence/absence, logs button callback, redeploy button for
  success/failed/running statuses, row id attribute, region flag

The dashboard page, all components (DeploymentList, DeploymentRow, AnalyticsCard,
AnalyticsGrid, HealthSummaryBar, DeploymentStatusBadge, DeploymentFiltersBar,
DeploymentListSkeleton), loading/empty/filtered states, and the fixture data were
already fully implemented.

closes #23