feat(frontend): polish remaining views + centralize time/status helpers

- Add formatDuration + formatRelativeTime to lib/format.ts and aiTone to
  lib/ai-status.ts; dedupe duplicated helpers in messages/analysis views.
- Recordings: upload-status badge (pending/processing/failed), channel chip,
  relative time, hover lift, surface upload errors.
- Media: mode pill + duration on now-playing, volume meter, per-track duration
  and queue total in header.
- Moderation: relative timestamps in action rows + executor hint.
- Analysis & Dashboard: rank bars for top reactors for scannable comparison.

services/frontend/src/lib/ai-status.ts

@@ -0,0 +1,13 @@
+import type { AiStatus } from "@/lib/types";
+
+export type AiTone = "signal" | "amber" | "vermilion" | "neutral";
+
+/**
+ * Map an AI analysis status to a design-system tone.
+ */
+export function aiTone(s?: AiStatus | null): AiTone {
+  if (s === "clean") return "signal";
+  if (s === "warn") return "amber";
+  if (s === "flagged" || s === "error") return "vermilion";
+  return "neutral";
+}

services/frontend/src/lib/format.ts

@@ -17,7 +17,41 @@ export function formatBytes(bytes: number): string {
 }
 
 /**
- * Safely parse a JSON string into an array.
+ * Human-readable duration, e.g. 850ms / 1.2s / 3m 12s.
+ */
+export function formatDuration(ms: number | null | undefined): string {
+  if (!ms || ms <= 0) return "";
+  if (ms < 1000) return `${Math.round(ms)}ms`;
+  const totalS = Math.floor(ms / 1000);
+  if (totalS < 60) return `${(ms / 1000).toFixed(1)}s`;
+  const m = Math.floor(totalS / 60);
+  const s = totalS % 60;
+  return s ? `${m}m ${s}s` : `${m}m`;
+}
+
+/**
+ * Compact relative time from an epoch-ms timestamp.
+ * e.g. "just now" / "5m" / "3h" / "2d" / "Apr 3".
+ */
+export function formatRelativeTime(ts?: number | null): string {
+  if (!ts) return "";
+  const diff = Date.now() - ts;
+  if (diff < 0) return new Date(ts).toLocaleDateString();
+  const m = Math.floor(diff / 60000);
+  if (m < 1) return "just now";
+  if (m < 60) return `${m}m`;
+  const h = Math.floor(m / 60);
+  if (h < 24) return `${h}h`;
+  const d = Math.floor(h / 24);
+  if (d < 7) return `${d}d`;
+  return new Date(ts).toLocaleDateString(undefined, {
+    month: "short",
+    day: "numeric",
+  });
+}
+
+/**
+ * Parse JSON string into array — safe.
  */
 export function safeParseJsonArray(value: string | null | undefined): string[] {
   if (!value) return [];