feat(portal-admin): audit dashboard — bar / donut / stacked-bar above the table

PR 3 of the charts chantier — closes the loop on ADR-0023 by
wiring the three starter components from #171 onto the /audit
page.

Three computed signals derive aggregations from the *current page's*
items (no new BFF endpoint — server-side stats land separately if
ever needed):

  * `dailyVolume` — events grouped by ISO date (YYYY-MM-DD).
  * `outcomeBreakdown` — counts per outcome.
  * `dailyByEventType` — flat (day, eventType, count) triples.

A new `<section class="charts">` renders above the existing filter
form, behind a `hasChartData()` guard so the section disappears
entirely on empty pages (no "0 events" donut, no half-rendered
bars). Each chart sits in a `.chart-tile`; the stacked-bar gets
`.chart-tile--wide` to span both grid columns since its legend
benefits from the extra horizontal space.

A `.charts-note` paragraph above the grid says explicitly that
the aggregations are "computed from the events currently loaded
on this page only" — honest disclosure of the per-page scope, no
misleading "all-time" framing.

Captions / descriptions / aria-labels live in plain English in the
template per ADR-0020's source-locale-only chrome posture. No new
i18n strings.

Bundle impact: the lazy `audit` chunk grows from ~4.4 KB to ~84 KB
gzip with the chart deps loaded — comfortable under [ADR-0017]'s
100 KB cap. The estimate in ADR-0023 was ~65 KB; Plot's full mark
set + d3-scale-chromatic interpolators add a bit more than
projected but still fit the budget.

Side tweaks:
  * `apps/portal-admin/project.json` bumps the `anyComponentStyle`
    budget from 5/6 KB to 6/8 KB to accommodate the charts grid
    SCSS (audit.scss lands at ~6.5 KB).
  * `apps/portal-admin/tsconfig.app.json` references the new
    `libs/shared/charts/tsconfig.lib.json` (auto-added by `nx
    sync` after the import in audit.ts).

Verification:
  * 57 portal-admin specs pass (was 54; +3 for the charts section
    rendering, the empty-page hide guard, and the donut center
    label binding).
  * `pnpm nx run-many -t lint test build --projects=portal-shell,
    portal-admin,shared-charts` — green.
  * Audit chunk gzip = 84 KB, under the budget.

apps/portal-admin/project.json

@@ -52,8 +52,8 @@
             },
             {
               "type": "anyComponentStyle",
-              "maximumWarning": "5kb",
+              "maximumWarning": "6kb",
-              "maximumError": "6kb"
+              "maximumError": "8kb"
             },
             {
               "type": "bundle",

apps/portal-admin/src/app/pages/audit/audit.html

@@ -113,7 +113,53 @@
     }
   </div>
 
-  @if (page(); as p) { @if (p.items.length === 0) {
+  @if (hasChartData()) {
+  <section class="charts" aria-labelledby="charts-h">
+    <h2 id="charts-h" class="charts-heading">At a glance — current page</h2>
+    <p class="charts-note">
+      Aggregations are computed from the events currently loaded on this page only. Apply filters or
+      change the page size to widen / narrow the window.
+    </p>
+    <div class="charts-grid">
+      <div class="chart-tile">
+        <lib-bar-chart
+          [data]="dailyVolume()"
+          xKey="day"
+          yKey="count"
+          xLabel="Date (UTC)"
+          yLabel="Events"
+          caption="Events per day"
+          description="Bar chart of audit event volume per calendar day for the events on this page."
+          ariaLabel="Events per day — bar chart"
+        />
+      </div>
+      <div class="chart-tile">
+        <lib-donut-chart
+          [data]="outcomeBreakdown()"
+          categoryKey="outcome"
+          valueKey="count"
+          [centerLabel]="totalOnPage().toString()"
+          caption="Outcome breakdown"
+          description="Donut chart of audit event outcomes (success, failure, denied) on this page."
+          ariaLabel="Outcome breakdown — donut chart"
+        />
+      </div>
+      <div class="chart-tile chart-tile--wide">
+        <lib-stacked-bar-chart
+          [data]="dailyByEventType()"
+          xKey="day"
+          yKey="count"
+          seriesKey="eventType"
+          xLabel="Date (UTC)"
+          yLabel="Events"
+          caption="Events per day, by event type"
+          description="Stacked bar chart of audit event volume per calendar day, broken down by event_type, for events on this page."
+          ariaLabel="Events per day, by event type — stacked bar chart"
+        />
+      </div>
+    </div>
+  </section>
+  } @if (page(); as p) { @if (p.items.length === 0) {
   <p class="empty">No audit events match the current filters.</p>
   } @else {
   <div class="table-wrap">

apps/portal-admin/src/app/pages/audit/audit.scss

@@ -194,6 +194,58 @@
   color: #9ca3af;
 }
 
+// Chart row above the table — same surface tokens as `.filters`
+// + `.table-wrap` so the page reads as one stack of related blocks.
+.charts {
+  margin: 0 0 1rem;
+  padding: 1rem;
+  background-color: #ffffff;
+  border: 1px solid #e5e7eb;
+  border-radius: 0.5rem;
+}
+
+:host-context(.dark) .charts {
+  background-color: #111827;
+  border-color: #1f2937;
+}
+
+.charts-heading {
+  margin: 0;
+  font-size: 0.875rem;
+  font-weight: 600;
+  color: #1f2937;
+
+  :where(.dark) & {
+    color: #f3f4f6;
+  }
+}
+
+.charts-note {
+  margin: 0.25rem 0 1rem;
+  font-size: 0.75rem;
+  color: #6b7280;
+
+  :where(.dark) & {
+    color: #9ca3af;
+  }
+}
+
+.charts-grid {
+  display: grid;
+  gap: 1rem;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+
+  @media (max-width: 800px) {
+    grid-template-columns: 1fr;
+  }
+}
+
+// The stacked-bar chart carries a legend and benefits from the
+// full width; flag it via a modifier and span both columns.
+.chart-tile--wide {
+  grid-column: 1 / -1;
+}
+
 .table-wrap {
   overflow-x: auto;
   background-color: #ffffff;

apps/portal-admin/src/app/pages/audit/audit.spec.ts

@@ -245,4 +245,35 @@ describe('AuditPage', () => {
     expect(row?.querySelector('.actor-hash--clickable')).toBeNull();
     expect(row?.querySelector('.actor-hash')?.textContent?.trim()).toBe('(anonymous)');
   });
+
+  describe('charts', () => {
+    it('renders the three chart tiles above the table when the page has data', async () => {
+      const { fixture } = setup();
+      await flush(fixture);
+      const root = fixture.nativeElement as HTMLElement;
+      expect(root.querySelector('section.charts')).not.toBeNull();
+      expect(root.querySelector('lib-bar-chart')).not.toBeNull();
+      expect(root.querySelector('lib-donut-chart')).not.toBeNull();
+      expect(root.querySelector('lib-stacked-bar-chart')).not.toBeNull();
+    });
+
+    it('hides the charts section when the page is empty (no aggregations to show)', async () => {
+      const empty: AdminAuditPage = { items: [], total: 0, limit: 50, offset: 0 };
+      const { fixture } = setup({ initial: empty });
+      await flush(fixture);
+      const root = fixture.nativeElement as HTMLElement;
+      expect(root.querySelector('section.charts')).toBeNull();
+    });
+
+    it('passes the donut a centerLabel matching the current page item count', async () => {
+      const { fixture } = setup();
+      await flush(fixture);
+      const root = fixture.nativeElement as HTMLElement;
+      // Donut's <details> fallback row count matches the categories;
+      // and the SVG carries the centre label as a <text> with the
+      // PAGE.items.length value.
+      const donutCenter = root.querySelector('lib-donut-chart .donut-center-label');
+      expect(donutCenter?.textContent?.trim()).toBe(String(PAGE.items.length));
+    });
+  });
 });

apps/portal-admin/src/app/pages/audit/audit.ts

@@ -1,6 +1,7 @@
 import { ChangeDetectionStrategy, Component, computed, inject, signal } from '@angular/core';
 import { FormsModule } from '@angular/forms';
 import { firstValueFrom } from 'rxjs';
+import { BarChart, DonutChart, StackedBarChart } from 'shared-charts';
 import { environment } from '../../../environments/environment';
 import {
   AuditEventsService,
@@ -31,7 +32,7 @@ const PAGE_SIZES = [25, 50, 100, 200] as const;
  */
 @Component({
   selector: 'app-audit-page',
-  imports: [FormsModule],
+  imports: [FormsModule, BarChart, DonutChart, StackedBarChart],
   templateUrl: './audit.html',
   styleUrl: './audit.scss',
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -87,6 +88,62 @@ export class AuditPage {
     return `${first}–${last} of ${p.total}`;
   });
 
+  // ---------------------------------------------------------------
+  // Chart aggregations — derived from the *current page only* per
+  // PR 3 of the charts chantier. The captions explicitly say so;
+  // server-side aggregations across the full filter set land in a
+  // separate chantier (would need a new `/api/admin/audit/stats`
+  // endpoint, out of scope for the v1 visual test).
+  // ---------------------------------------------------------------
+
+  /** Total event count for the current page — drives the donut's centre label. */
+  protected readonly totalOnPage = computed(() => this.page()?.items.length ?? 0);
+
+  /** Events grouped by ISO date (YYYY-MM-DD) on the current page. */
+  protected readonly dailyVolume = computed(() => {
+    const items = this.page()?.items ?? [];
+    const buckets = new Map<string, number>();
+    for (const ev of items) {
+      const day = ev.createdAt.slice(0, 10);
+      buckets.set(day, (buckets.get(day) ?? 0) + 1);
+    }
+    return Array.from(buckets, ([day, count]) => ({ day, count })).sort((a, b) =>
+      a.day.localeCompare(b.day),
+    );
+  });
+
+  /** Outcome counts on the current page (success / failure / denied). */
+  protected readonly outcomeBreakdown = computed(() => {
+    const items = this.page()?.items ?? [];
+    const buckets = new Map<string, number>();
+    for (const ev of items) {
+      buckets.set(ev.outcome, (buckets.get(ev.outcome) ?? 0) + 1);
+    }
+    return Array.from(buckets, ([outcome, count]) => ({ outcome, count }));
+  });
+
+  /**
+   * Daily counts split by event_type for the current page. The
+   * stacked-bar component pre-pivots internally — we feed a flat
+   * (day, eventType, count) triple.
+   */
+  protected readonly dailyByEventType = computed(() => {
+    const items = this.page()?.items ?? [];
+    const buckets = new Map<string, number>();
+    for (const ev of items) {
+      const day = ev.createdAt.slice(0, 10);
+      const key = `${day}::${ev.eventType}`;
+      buckets.set(key, (buckets.get(key) ?? 0) + 1);
+    }
+    return Array.from(buckets, ([key, count]) => {
+      const [day, eventType] = key.split('::');
+      return { day: day ?? '', eventType: eventType ?? '', count };
+    }).sort((a, b) => a.day.localeCompare(b.day) || a.eventType.localeCompare(b.eventType));
+  });
+
+  /** Whether any chart has enough data to be worth rendering. */
+  protected readonly hasChartData = computed(() => (this.page()?.items.length ?? 0) > 0);
+
   /**
    * Run a new query with the current filter signals at offset 0.
    * Called by the "Apply filters" button + the initial render via

apps/portal-admin/tsconfig.app.json

@@ -7,6 +7,9 @@
   "include": ["src/**/*.ts"],
   "exclude": ["src/**/*.spec.ts", "src/**/*.test.ts"],
   "references": [
+    {
+      "path": "../../libs/shared/charts/tsconfig.lib.json"
+    },
     {
       "path": "../../libs/shared/ui/tsconfig.lib.json"
     },