feat: restyle Admin UI with the technical-light design system

Adopt the technical-light design system across the Admin web UI:

- Vendor theme.css + IBM Plex woff2 fonts into wwwroot; include
  theme.css globally after Bootstrap.
- Rebuild MainLayout: top app-bar (brand mark, breadcrumb, connection
  pill) + hairline-ruled side rail with accent-bordered active link.
- Convert all 33 pages to the component catalog — tables to
  panel + data-table (num/mono columns), KPI cards to agg-grid,
  detail blocks to metric-card/kv rows, badges to chips, alerts to
  panel notice, headings to page-title/panel-head, .rise reveals.
- Buttons/forms stay on Bootstrap; theme.css restyles them via
  --bs-* overrides. View-specific layout lives in app.css; all
  colour/type comes from theme.css tokens.

Also fix a pre-existing /fleet 500: the node-state query ordered on
a property of a constructed FleetNodeRow record, which EF Core
cannot translate. Order the join's columns before projecting.

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

src/Server/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/app.css

@@ -1,3 +1,105 @@
-/* OtOpcUa Admin — ScadaLink-parity palette. Keep it minimal here; lean on Bootstrap 5. */
-body { background-color: #f5f6fa; }
-.nav-link.active { background-color: rgba(255,255,255,0.1); border-radius: 4px; }
+/* OtOpcUa Admin — view-specific layer over the technical-light theme (theme.css).
+   Tokens live in theme.css; this sheet only carries layout + the side rail. */
+
+/* ── App shell: side rail + page ─────────────────────────────────────────── */
+.app-shell {
+    display: flex;
+    align-items: stretch;
+    min-height: calc(100vh - 3.3rem);
+}
+
+.app-shell .page {
+    flex: 1;
+    min-width: 0;
+}
+
+/* ── Side rail ───────────────────────────────────────────────────────────── */
+.side-rail {
+    width: 218px;
+    flex: 0 0 218px;
+    display: flex;
+    flex-direction: column;
+    gap: 0.15rem;
+    padding: 1rem 0.7rem;
+    background: var(--card);
+    border-right: 1px solid var(--rule-strong);
+}
+
+.rail-eyebrow {
+    font-size: 0.68rem;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.07em;
+    color: var(--ink-faint);
+    padding: 0.3rem 0.6rem;
+}
+
+.rail-link {
+    display: block;
+    padding: 0.4rem 0.6rem;
+    border-radius: 4px;
+    border-left: 2px solid transparent;
+    font-size: 0.86rem;
+    color: var(--ink-soft);
+}
+.rail-link:hover {
+    background: #f3f6fd;
+    color: var(--ink);
+    text-decoration: none;
+}
+.rail-link.active {
+    background: #eef2fc;
+    border-left-color: var(--accent);
+    color: var(--accent-deep);
+    font-weight: 600;
+}
+
+/* ── Session block, pinned to the rail foot ──────────────────────────────── */
+.rail-foot {
+    margin-top: auto;
+    padding-top: 0.6rem;
+    border-top: 1px solid var(--rule);
+}
+.rail-user {
+    display: block;
+    padding: 0 0.6rem;
+    font-weight: 600;
+    font-size: 0.88rem;
+}
+.rail-roles {
+    padding: 0.1rem 0.6rem 0.5rem;
+    font-family: var(--mono);
+    font-size: 0.72rem;
+    color: var(--ink-faint);
+}
+.rail-btn {
+    display: inline-block;
+    margin: 0 0.6rem;
+    padding: 0.3rem 0.7rem;
+    font-size: 0.78rem;
+    font-weight: 600;
+    color: var(--ink-soft);
+    background: var(--card);
+    border: 1px solid var(--rule-strong);
+    border-radius: 4px;
+    cursor: pointer;
+}
+.rail-btn:hover {
+    border-color: var(--accent);
+    color: var(--accent);
+    text-decoration: none;
+}
+
+/* ── Page headings — uppercase eyebrow, calm spacing ─────────────────────── */
+.page-title {
+    font-size: 1.15rem;
+    font-weight: 600;
+    margin: 0 0 1rem;
+    color: var(--ink);
+}
+
+/* ── Login card centring ─────────────────────────────────────────────────── */
+.login-wrap {
+    max-width: 380px;
+    margin: 3.5rem auto 0;
+}