refactor(frontend): finish shadcn→custom primitive migration (green build)

- Remove tw-animate-css import + dead src/components/ui shadcn tree
- Convert 7 orphaned components (moderation, analysis, guild-selector,
  voice/activity-timeline, shared/empty+error) to new primitives
- Add missing moderation/view.tsx; analysis uses SearchPanel directly
- globals.css now uses new signal-driven ops-console tokens
- tsc --noEmit clean, next build green (11 routes), local smoke 200

services/frontend/src/components/primitives/avatar.tsx

@@ -0,0 +1,39 @@
+import { cn } from "@/lib/utils";
+
+export interface AvatarProps {
+  src?: string | null;
+  name?: string | null;
+  size?: number;
+  className?: string;
+}
+
+function initials(name?: string | null): string {
+  if (!name) return "?";
+  const parts = name.trim().split(/\s+/);
+  if (parts.length === 1) return parts[0].slice(0, 2).toUpperCase();
+  return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase();
+}
+
+export function Avatar({ src, name, size = 36, className }: AvatarProps) {
+  return (
+    <span
+      className={cn(
+        "relative inline-flex shrink-0 items-center justify-center overflow-hidden rounded-full",
+        "bg-[var(--color-signal)]/20 text-[var(--color-signal)] font-semibold",
+        className,
+      )}
+      style={{ width: size, height: size, fontSize: size * 0.38 }}
+    >
+      {src ? (
+        <img
+          src={src}
+          alt={name ?? ""}
+          className="size-full object-cover"
+          loading="lazy"
+        />
+      ) : (
+        initials(name)
+      )}
+    </span>
+  );
+}