feat(agent-team): render all dashboard times as Eastern 24h (EDT/EST)

Add src/lib/time.ts formatEastern() — parses both backend timestamp shapes
(the 'YYYY-MM-DD HH:MM:SS UTC' snapshot string and ISO offset transition times),
renders them in America/New_York (DST-aware: EDT/EST) as 24h
'YYYY-MM-DD HH:MM:SS ZZZ'. Wire into TopBar (snapshot clock + tooltip) and the
TaskDrawer timeline (entered_at). Adds time.test.ts (8 cases incl. DST + day
boundary). 44 frontend tests green.

agent-team/web/src/components/TaskDrawer.tsx

@@ -12,6 +12,7 @@ import {
   CollapsibleContent,
 } from "@/components/ui/collapsible";
 import { cn } from "@/lib/utils";
+import { formatEastern } from "@/lib/time";
 
 interface Props {
   detail: TaskDetail | null;
@@ -171,8 +172,8 @@ export function TaskDrawer({ detail, loading, error, onClose }: Props) {
                         </div>
                         <div className="flex items-center gap-2 mt-0.5 flex-wrap">
                           {step.entered_at && (
-                            <span className="text-xs text-muted-foreground">
-                              {step.entered_at}
+                            <span className="text-xs text-muted-foreground tabular-nums">
+                              {formatEastern(step.entered_at)}
                             </span>
                           )}
                           {step.status && (

agent-team/web/src/components/TopBar.tsx

@@ -1,4 +1,5 @@
 import { cn } from "@/lib/utils";
+import { formatEastern } from "@/lib/time";
 import type { StateResponse } from "../api";
 
 interface Props {
@@ -50,9 +51,10 @@ const CHIPS: ChipDef[] = [
 // Top status bar: brand, summary chips, connection health, and snapshot clock.
 export function TopBar({ state, connected, generatedAt }: Props) {
   const summary = state?.summary;
+  const snapshot = formatEastern(generatedAt);
   const title = connected
-    ? `Live — snapshot at ${generatedAt ?? "—"}`
-    : `Disconnected — last snapshot at ${generatedAt ?? "—"}`;
+    ? `Live — snapshot at ${snapshot}`
+    : `Disconnected — last snapshot at ${snapshot}`;
 
   return (
     <header
@@ -117,7 +119,7 @@ export function TopBar({ state, connected, generatedAt }: Props) {
           )}
         />
         <span className="text-xs text-muted-foreground tabular-nums">
-          {generatedAt ?? "—"}
+          {snapshot}
         </span>
       </div>
     </header>

agent-team/web/src/lib/time.test.ts

@@ -0,0 +1,55 @@
+import { describe, expect, it } from "vitest";
+import { formatEastern, parseServerDate } from "./time";
+
+describe("formatEastern", () => {
+  it("formats the snapshot 'YYYY-MM-DD HH:MM:SS UTC' shape as Eastern 24h (EDT in summer)", () => {
+    // 22:54:48 UTC on 2026-06-24 is 18:54:48 EDT (UTC-4).
+    expect(formatEastern("2026-06-24 22:54:48 UTC")).toBe(
+      "2026-06-24 18:54:48 EDT",
+    );
+  });
+
+  it("formats ISO offset timestamps as Eastern 24h", () => {
+    expect(formatEastern("2026-06-24T22:48:10.437876+00:00")).toBe(
+      "2026-06-24 18:48:10 EDT",
+    );
+  });
+
+  it("uses EST in winter (DST-aware)", () => {
+    // 12:00 UTC on 2026-01-15 is 07:00 EST (UTC-5).
+    expect(formatEastern("2026-01-15 12:00:00 UTC")).toBe(
+      "2026-01-15 07:00:00 EST",
+    );
+  });
+
+  it("crosses the day boundary correctly (late UTC -> earlier Eastern, prior day)", () => {
+    // 02:30 UTC on 2026-06-25 is 22:30 EDT on 2026-06-24.
+    expect(formatEastern("2026-06-25T02:30:00+00:00")).toBe(
+      "2026-06-24 22:30:00 EDT",
+    );
+  });
+
+  it("returns the em-dash for null / undefined / unparseable input", () => {
+    expect(formatEastern(null)).toBe("—");
+    expect(formatEastern(undefined)).toBe("—");
+    expect(formatEastern("not a date")).toBe("—");
+  });
+});
+
+describe("parseServerDate", () => {
+  it("treats the bare 'UTC'-suffixed shape as UTC", () => {
+    const d = parseServerDate("2026-06-24 22:54:48 UTC");
+    expect(d?.toISOString()).toBe("2026-06-24T22:54:48.000Z");
+  });
+
+  it("parses ISO offsets", () => {
+    const d = parseServerDate("2026-06-24T22:48:10.000+00:00");
+    expect(d?.toISOString()).toBe("2026-06-24T22:48:10.000Z");
+  });
+
+  it("returns null for empty/unparseable input", () => {
+    expect(parseServerDate(null)).toBeNull();
+    expect(parseServerDate("")).toBeNull();
+    expect(parseServerDate("nope")).toBeNull();
+  });
+});

agent-team/web/src/lib/time.ts

@@ -0,0 +1,43 @@
+// Time formatting for the dashboard. All backend timestamps are UTC; we render
+// them in US Eastern (America/New_York — EDT in summer, EST in winter, DST-aware)
+// as 24-hour `YYYY-MM-DD HH:MM:SS ZZZ`.
+//
+// The backend emits two shapes:
+//   - "2026-06-24 22:54:48 UTC"            (status snapshot generated_at)
+//   - "2026-06-24T22:48:10.437876+00:00"   (ISO transition timestamps)
+// parseServerDate normalizes both to a Date; everything else is ISO that the
+// JS engine parses natively.
+
+const EASTERN_FMT = new Intl.DateTimeFormat("en-CA", {
+  timeZone: "America/New_York",
+  year: "numeric",
+  month: "2-digit",
+  day: "2-digit",
+  hour: "2-digit",
+  minute: "2-digit",
+  second: "2-digit",
+  hourCycle: "h23", // 24-hour, 00–23 (never "24:xx")
+  timeZoneName: "short",
+});
+
+/** Parse a backend timestamp (UTC) into a Date, or null if unparseable. */
+export function parseServerDate(raw: string | null | undefined): Date | null {
+  if (!raw) return null;
+  let s = String(raw).trim();
+  // "YYYY-MM-DD HH:MM:SS UTC" -> ISO "YYYY-MM-DDTHH:MM:SSZ"
+  if (s.endsWith(" UTC")) s = s.slice(0, -4).trim().replace(" ", "T") + "Z";
+  const d = new Date(s);
+  return Number.isNaN(d.getTime()) ? null : d;
+}
+
+/**
+ * Format a backend UTC timestamp as Eastern 24-hour time:
+ * "2026-06-24 18:54:48 EDT". Returns "—" for null/unparseable input.
+ */
+export function formatEastern(raw: string | null | undefined): string {
+  const d = parseServerDate(raw);
+  if (!d) return "—";
+  const p: Record<string, string> = {};
+  for (const part of EASTERN_FMT.formatToParts(d)) p[part.type] = part.value;
+  return `${p.year}-${p.month}-${p.day} ${p.hour}:${p.minute}:${p.second} ${p.timeZoneName}`;
+}