feat(web): adopt @vincjo/datatables for all tables, standardize shared components

- Add DataTable.svelte: declarative columns, built-in sorting, sticky headers,
  text truncation, column alignment, configurable widths, optional pagination/search
- 12 built-in renderers: BadgeRenderer, StatusBadgeRenderer (unified risk/severity/
  execution/state/type variant mapping), HealthDotRenderer, RelativeTimeRenderer,
  DateRenderer, DurationRenderer, StatusDotRenderer, SignalActions, ApprovalActions,
  ActivityAction, ActivityCancel
- Migrate Overview (task board), Signals, Ops (3 tables) to DataTable
- Refactor EntityTable treegrid to use shared SortHeader, EmptyState, HealthDotRenderer
- Create shared components: EmptyState, StatusBadge, FilterTabs
- Clean up Knowledge.svelte: replace inline relTime() and typeVariant() with shared utils
- Add width, align, truncate column props; table-fixed layout; rounded-xl borders
- Bump version to 0.11.0

web/src/lib/components/data-table/renderers/SignalActions.svelte

@@ -0,0 +1,26 @@
+<script lang="ts">
+  import { Button } from '$lib/components/ui/button'
+  import type { Signal } from '$lib/api'
+
+  let {
+    row,
+    acting = null,
+    onAck,
+    onMute,
+    onResolve
+  }: {
+    row: Signal
+    acting?: string | null
+    onAck?: (id: string) => void
+    onMute?: (id: string) => void
+    onResolve?: (id: string) => void
+  } = $props()
+</script>
+
+<div class="flex justify-end gap-2">
+  {#if row.state === 'raised'}
+    <Button size="sm" variant="outline" disabled={acting === row.id} onclick={() => onAck?.(row.id)}>Ack</Button>
+  {/if}
+  <Button size="sm" variant="outline" disabled={acting === row.id} onclick={() => onMute?.(row.id)}>Mute 1h</Button>
+  <Button size="sm" disabled={acting === row.id} onclick={() => onResolve?.(row.id)}>Resolve</Button>
+</div>