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/tooltip.tsx

@@ -0,0 +1,50 @@
+"use client";
+
+import { type ReactNode, useState } from "react";
+import { cn } from "@/lib/utils";
+
+export interface TooltipProps {
+  content: ReactNode;
+  children: ReactNode;
+  side?: "top" | "bottom" | "left" | "right";
+  className?: string;
+}
+
+const sidePos: Record<NonNullable<TooltipProps["side"]>, string> = {
+  top: "bottom-full left-1/2 -translate-x-1/2 mb-2",
+  bottom: "top-full left-1/2 -translate-x-1/2 mt-2",
+  left: "right-full top-1/2 -translate-y-1/2 mr-2",
+  right: "left-full top-1/2 -translate-y-1/2 ml-2",
+};
+
+export function Tooltip({
+  content,
+  children,
+  side = "top",
+  className,
+}: TooltipProps) {
+  const [show, setShow] = useState(false);
+  return (
+    <span
+      className="relative inline-flex"
+      onMouseEnter={() => setShow(true)}
+      onMouseLeave={() => setShow(false)}
+      onFocus={() => setShow(true)}
+      onBlur={() => setShow(false)}
+    >
+      {children}
+      <span
+        role="tooltip"
+        className={cn(
+          "pointer-events-none absolute z-50 whitespace-nowrap rounded-[var(--radius-r-control)] px-2.5 py-1 text-xs font-medium",
+          "bg-[var(--color-ink)] text-[var(--color-canvas)] opacity-0 transition-opacity duration-150",
+          sidePos[side],
+          show && "opacity-100",
+          className,
+        )}
+      >
+        {content}
+      </span>
+    </span>
+  );
+}