fix(web): profile modal always displayed UTC — Timezone never mapped

The admin profile-modal route hand-rolled its templates.User without
the Timezone field, so every selected?={ user.Timezone == … } in the
timezone select was false and the first option (UTC) rendered selected
for every user on every open. Saves worked fine — the modal just never
displayed what was stored, which read as 'not saving'. The route's
GetUser query already returns the column; it just wasn't mapped.
Verified end-to-end in the emulator browser: modal opens showing the
stored zone, save → HX-Refresh → reopen shows the new zone.

internal/router/frontend.go

@@ -1254,6 +1254,9 @@ func registerFrontendRoutes(cfg *Config) {
 			FirstName: getText(targetUser.FirstName),
 			LastName:  getText(targetUser.LastName),
 			CreatedAt: targetUser.CreatedAt.Time,
+			// Without this the timezone select rendered UTC selected for
+			// EVERY user — saves landed, the modal just never showed them.
+			Timezone: getText(targetUser.Timezone),
 		}
 
 		// Render modal