fix(dreaming): include timezone label in diary timestamps (#65057)

Dream diary entries in DREAMS.md and the Control UI show bare
timestamps without any timezone indicator. When users have not
configured a timezone, timestamps are rendered in UTC but appear to be
local time, causing confusion.

Add timeZoneName: "short" to the Intl.DateTimeFormat options in
formatNarrativeDate so timestamps always include a timezone
abbreviation (e.g. "9:46 PM UTC" or "2:46 PM PDT").

Fixes #65027

extensions/memory-core/src/dreaming-narrative.test.ts

@@ -121,6 +121,7 @@ describe("formatNarrativeDate", () => {
     expect(date).toContain("April");
     expect(date).toContain("2026");
     expect(date).toContain("3:00");
+    expect(date).toContain("UTC");
   });
 
   it("applies an explicit timezone", () => {
@@ -131,6 +132,7 @@ describe("formatNarrativeDate", () => {
     );
     expect(date).toContain("2:46");
     expect(date).toContain("PM");
+    expect(date).toContain("PDT");
   });
 
   it("uses host local timezone when timezone is undefined (#65027)", () => {
@@ -144,6 +146,7 @@ describe("formatNarrativeDate", () => {
       // 21:46 UTC → 14:46 PDT → "2:46 PM"
       expect(result).toContain("2:46");
       expect(result).toContain("PM");
+      expect(result).toContain("PDT");
     } finally {
       if (originalTZ === undefined) {
         delete process.env.TZ;

extensions/memory-core/src/dreaming-narrative.ts

@@ -238,6 +238,11 @@ export function formatNarrativeDate(epochMs: number, timezone?: string): string
     hour: "numeric",
     minute: "2-digit",
     hour12: true,
+    // Always include the timezone abbreviation so the reader knows which
+    // timezone the timestamp refers to.  Without this, users who haven't
+    // configured a timezone see bare times that look local but are actually
+    // UTC, causing confusion (see #65027).
+    timeZoneName: "short",
   };
   return new Intl.DateTimeFormat("en-US", opts).format(new Date(epochMs));
 }