refactor(system-info): reduce to Stripe-style status page

Reduce admin/system-info to a single focused status view: overall
status banner, components list from existing health checks, and an
environment meta table. Drops the Modules and Permissions tabs —
those were dev-diagnostics already available via CLI.

- Remove SystemInfoService + its test; wire the action directly to
  SystemHealthService and build meta inline
- Extend SystemHealthService with per-check label + description so
  the UI speaks in customer terms while the CLI doctor path stays
  compatible
- Rebuild the view on existing app-stats-table + app-empty-state
  primitives; add a small app-status-banner component for the
  headline signal
- Align help-center nav label and i18n keys (de/en)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/css/components/app-status-banner.css

@@ -0,0 +1,74 @@
+@layer components {
+  .app-status-banner {
+    display: flex;
+    align-items: center;
+    gap: 18px;
+    padding: calc(var(--app-spacing) * 1) calc(var(--app-spacing) * 1.25);
+    border: 1px solid var(--badge-neutral-border);
+    border-radius: var(--app-border-radius);
+    background: var(--badge-neutral-bg);
+    color: var(--badge-neutral-color);
+    margin-block-end: var(--app-spacing);
+  }
+
+  .app-status-banner[data-variant="success"] {
+    background: var(--badge-success-bg);
+    color: var(--badge-success-color);
+    border-color: var(--badge-success-border);
+  }
+
+  .app-status-banner[data-variant="warn"] {
+    background: var(--badge-warn-bg);
+    color: var(--badge-warn-color);
+    border-color: var(--badge-warn-border);
+  }
+
+  .app-status-banner[data-variant="danger"] {
+    background: var(--badge-danger-bg);
+    color: var(--badge-danger-color);
+    border-color: var(--badge-danger-border);
+  }
+
+  .app-status-banner > i {
+    font-size: var(--text-3xl);
+    line-height: var(--leading-none);
+    flex-shrink: 0;
+  }
+
+  .app-status-banner-text {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+    min-width: 0;
+  }
+
+  .app-status-banner-text h2 {
+    margin: 0;
+    font-size: var(--text-lg);
+    line-height: var(--leading-snug);
+  }
+
+  .app-status-banner-text small {
+    opacity: 0.85;
+  }
+
+  .app-stats-table .app-status-description {
+    display: block;
+    color: var(--app-muted-color);
+    margin-top: 2px;
+  }
+
+  .app-stats-table td.app-status-badge-cell {
+    text-align: end;
+    white-space: nowrap;
+    width: 1%;
+  }
+
+  @media (max-width: 600px) {
+    .app-status-banner {
+      flex-direction: column;
+      align-items: flex-start;
+      text-align: start;
+    }
+  }
+}