feat(portal-shell): app-shell layout with collapsable sidebar

Switch the SPA from header+main+footer to a fixed header above a
sidebar/main split. The sidebar carries grouped navigation, can be
collapsed to an icon-only rail (state persisted in localStorage), and
hosts the accessibility-statement links the footer used to own. Adds
brand palette tokens (primary teal #12546c, accent orange #f7a919) as
Tailwind v4 @theme entries, an <app-icon> façade over lucide-angular
so the future icomoon sprite migration is a single-file change, and
the APF logo asset under public/logos/.

Menu data is static for v1 — items point to '#' placeholders, with the
Dashboard entry routerLink-bound so the active-state styling is
visible on the home page. The MenuItem shape already carries an
optional requiredPermissions field so the permission-aware filter (to
land alongside the auth flow per ADR-0009) plugs in without
restructuring. WCAG-relevant choices preserved: skip-link, role/aria
landmarks, aria-current="page" on active links, aria-expanded on the
toggle, prefers-reduced-motion respected on width transitions, and a
44px minimum hit-target on every interactive element (ADR-0016).

Footer component removed — its links migrated to the sidebar bottom.

package.json

@@ -141,6 +141,7 @@
     "axios": "^1.6.0",
     "class-transformer": "^0.5.1",
     "class-validator": "^0.15.1",
+    "lucide-angular": "^1.0.0",
     "nestjs-cls": "^6.2.0",
     "nestjs-pino": "^4.6.1",
     "nestjs-prisma": "^0.27.0",