feat(ui): use timezone-aware time formatting across all templates

Replace hardcoded .Format() calls with FormatInTimezone() and
FormatTimestamptzInTimezone() helpers so all timestamps display in
the user's selected timezone.

Changes:
- book_detail.templ: remove incorrect templates. package prefix
- book_detail_modals.templ: add User param to ProgressSyncModal so
  timezone is available; convert Timestamp to FormatInTimezone()
- devices.templ: convert LastSync and LastSeen to FormatInTimezone()
- conflicts.templ: convert CreatedAt to FormatInTimezone()
- admin_users.templ: convert CreatedAt to FormatInTimezone() using
  currentUser.Timezone

Note: DatePublished is kept as a plain date format (MM-DD-YYYY) since
it is a pgtype.Date, not a timestamp, and does not need timezone
conversion.

templates/book_detail.templ

@@ -250,7 +250,7 @@ templ BookDetail(user User, book handlers.MediaDetail, errorMessage string) {
 							if book.ReadingProgress.LastReadAt.Valid {
 								<div>
 									<p style="color: var(--text-secondary)">Last Read</p>
-									<p>{ templates.FormatTimestamptzInTimezone(book.ReadingProgress.LastReadAt, user.Timezone) }</p>
+									<p>{ FormatTimestamptzInTimezone(book.ReadingProgress.LastReadAt, user.Timezone) }</p>
 								</div>
 							}
 							if book.ReadingProgress.LastSyncSource.Valid {
@@ -501,7 +501,7 @@ templ BookDetail(user User, book handlers.MediaDetail, errorMessage string) {
 				}
 			</div>
 			<!-- Modals -->
-			@ProgressSyncModal(book)
+			@ProgressSyncModal(user, book)
 			@NotesHighlightsModal(book)
 			@ErrorToast(errorMessage)
 		</body>