fix: use UTC timezone in formatRelativeTime to avoid snapshot drift

toLocaleDateString() without a timezone produces different dates
depending on the machine's timezone, causing snapshot mismatches
between local (KST) and CI (UTC).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: limgit

src/utils/display.ts

@@ -86,6 +86,6 @@ export function formatRelativeTime(dateString: string): string {
   } else if (diffDays < 7) {
     return diffDays === 1 ? "1 day ago" : `${diffDays} days ago`
   } else {
-    return commentDate.toLocaleDateString()
+    return commentDate.toLocaleDateString(undefined, { timeZone: "UTC" })
   }
 }

test/commands/issue/__snapshots__/issue-view.test.ts.snap

@@ -70,7 +70,7 @@ Users are experiencing issues logging in when their session expires.
 
 ## Comments
 
-- **@Bob Senior** - *1/16/2024*
+- **@Bob Senior** - *1/15/2024*
 
   Should we also consider implementing automatic session refresh?
 
@@ -82,7 +82,7 @@ Users are experiencing issues logging in when their session expires.
 
     Working on a fix. Will increase the session timeout and add proper error handling.
 
-  - **@Alice Developer** - *1/16/2024*
+  - **@Alice Developer** - *1/15/2024*
 
     Sounds good! Also, we should add better error messaging for expired sessions.