fix(GRO-2299): redact googleMapsApiKey from PATCH /api/admin/settings response

The PATCH handler returned the full businessSettings row via .returning(),
echoing the encrypted googleMapsApiKey ciphertext back to the caller. Wrap the
return in the existing redactSettings() helper (after a !updated guard) so
redaction is applied symmetrically with the GET projection (GRO-2294).

- src/routes/settings.ts: guard + redactSettings(updated) on PATCH return
- src/__tests__/settings.test.ts: assert PATCH omits googleMapsApiKey
  (existing-row and auto-create-then-update branches)
- UAT_PLAYBOOK.md §13 TC-API-13.2: assert PATCH response omits the secret

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/routes/settings.ts

@@ -65,7 +65,8 @@ settingsRouter.patch(
       .where(eq(businessSettings.id, settingsId))
       .returning();
 
-    return c.json(updated);
+    if (!updated) throw new Error("Failed to update settings");
+    return c.json(redactSettings(updated));
   }
 );