Frontend redesign chunk 2: primitives and marks

Rewrite components/ui/* (Button, Card, Badge, PageHeader, EmptyState,
Skeleton) against the chunk-1 tokens instead of hardcoded gray-9xx classes,
and drop the remaining font-mono from label/heading text.

Add the three colour-blindness-validated encoding components from
UI_REDESIGN.md §2.3:
- components/marks/SeverityMark.tsx — glyph (filled triangle / outline
  triangle / outline circle) + optional spine + optional label, from the
  four-level severity ladder. Colour is never the only channel.
- components/marks/TypeGlyph.tsx — five stroked SVG glyphs (fire, police,
  ems, collision, other) in currentColor. Incident type is now shape, not
  hue, since five hues can't clear an all-pairs CVD gate.
- components/marks/NodeMark.tsx — diamond at four weights (filled+ring /
  filled / hollow / hollow-dashed). Green is gone from node state entirely.

lib/severity.tsx now renders through SeverityMark; SEVERITY_COLORS reads
the validated sev-moderate/sev-major tokens with routine/minor neutral.
IncidentBadges.tsx's TypeBadge is reimplemented on TypeGlyph instead of a
coloured pill.

Per UI_REDESIGN.md chunk 2.

drb-frontend/components/IncidentBadges.tsx

@@ -3,19 +3,26 @@
 // the four radio-traffic archetypes (rail ops, public works, utility
 // coordination, …) and must always resolve to a styled badge, never fall
 // through unstyled.
-const TYPE_COLORS: Record<string, string> = {
-  fire:     "bg-red-900 text-red-300",
-  police:   "bg-blue-900 text-blue-300",
-  ems:      "bg-yellow-900 text-yellow-300",
-  accident: "bg-orange-900 text-orange-300",
-  other:    "bg-gray-800 text-gray-300",
+//
+// Type is carried by SHAPE (TypeGlyph), never hue — see UI_REDESIGN.md §2.3.
+// This badge is the transitional/list-row form: glyph + word in neutral ink.
+import { TypeGlyph } from "@/components/marks/TypeGlyph";
+
+const TYPE_LABEL: Record<string, string> = {
+  fire: "Fire",
+  police: "Police",
+  ems: "EMS",
+  accident: "Collision",
+  collision: "Collision",
+  other: "Other",
 };
 
 export function TypeBadge({ type }: { type: string | null }) {
-  const cls = TYPE_COLORS[type ?? "other"] ?? TYPE_COLORS.other;
+  const label = TYPE_LABEL[type ?? "other"] ?? TYPE_LABEL.other;
   return (
-    <span className={`text-xs font-mono px-2 py-0.5 rounded-full capitalize ${cls}`}>
-      {type ?? "other"}
+    <span className="inline-flex items-center gap-1.5 text-xs font-medium px-2 py-0.5 rounded-full bg-raised text-ink-2">
+      <TypeGlyph type={type} size={16} />
+      {label}
     </span>
   );
 }