Redesign UI with new token system, primitives, and motion

Restraint-first design language: neutral gray surfaces + one blue accent
(cyan/amber/red reserved for state), 8pt spacing, softer radii, one
ambient + one raised shadow, standardized motion tokens. Alfa Slab One
demoted to BrandMark only; Inter carries all page copy.

New primitives (Button, Card, Badge, Stat, SectionHeader, Skeleton,
EmptyState, Tabs, Breadcrumbs, StatusPip, Field, Input, Select, Textarea)
plus motion utilities (tweenNumber, viewTransition) and a global toast
system. All eight route surfaces rewritten on top: Fleet gains an
overview hero, Server detail restructures into tabs, Deployments gets a
collapsible drift summary + per-server pipeline visual, and the
scripts/configs/plugins/betas flows adopt the new form primitives.

Sticky translucent nav with backdrop blur, view-transition cross-fades
between routes, staggered card entrance on Fleet, breathing status pip
halo, tabular-numeric player counts. Gmail-style g-key nav shortcuts.
Mobile stacks below 720px; prefers-reduced-motion neutralizes durations.
Legacy tokens preserved as aliases so any un-migrated code still renders.

src/lib/ui/components/BrandMark.svelte

@@ -1,4 +1,8 @@
 <script lang="ts">
+    // Alfa Slab One is imported *here*, not globally, so the rest of the
+    // product doesn't pay for a display face it never uses.
+    import '@fontsource/alfa-slab-one/400.css';
+
     interface Props {
         size?: 'sm' | 'md' | 'lg';
     }