fix(shared): show zero seconds in minute durations

apps/mobile/src/features/threads/subagent-card-presentation.test.ts

@@ -22,7 +22,7 @@ describe("subagent card", () => {
     expect(subagentCardElapsed([unfinished], DateTime.toEpochMillis(later))).toBeNull();
     expect(
       subagentCardElapsed([{ ...unfinished, status: "running" }], DateTime.toEpochMillis(later)),
-    ).toBe("2m");
+    ).toBe("2m 0s");
     expect(
       subagentCardElapsed([{ ...unfinished, status: "idle" }], DateTime.toEpochMillis(later)),
     ).toBeNull();

packages/shared/src/orchestrationTiming.test.ts

@@ -1,6 +1,20 @@
 import { describe, expect, it } from "vite-plus/test";
 
-import { deriveSubagentElapsedMs } from "./orchestrationTiming.ts";
+import { deriveSubagentElapsedMs, formatDuration } from "./orchestrationTiming.ts";
+
+describe("formatDuration", () => {
+  it.each([
+    [59_000, "59s"],
+    [59_500, "1m 0s"],
+    [60_000, "1m 0s"],
+    [720_000, "12m 0s"],
+    [736_000, "12m 16s"],
+    [3_600_000, "1h"],
+    [3_660_000, "1h 1m 0s"],
+  ])("formats %i milliseconds as %s", (durationMs, expected) => {
+    expect(formatDuration(durationMs)).toBe(expected);
+  });
+});
 
 describe("deriveSubagentElapsedMs", () => {
   const startedAt = "2026-09-21T12:00:00.000Z";

packages/shared/src/orchestrationTiming.ts

@@ -32,6 +32,6 @@ export function formatDuration(durationMs: number): string {
   const parts: string[] = [];
   if (hours > 0) parts.push(`${hours}h`);
   if (minutes > 0) parts.push(`${minutes}m`);
-  if (seconds > 0) parts.push(`${seconds}s`);
+  if (seconds > 0 || minutes > 0) parts.push(`${seconds}s`);
   return parts.join(" ");
 }