A shop can be renamed and, while empty, removed - from head office

The display name was always meant to be editable and the slug frozen;
until now neither had a way in. PATCH /api/sites/{site} takes a name
and a timezone (manager and above), DELETE removes an empty shop
(owner). The shop drawer in head office gets both, with the short name
shown read-only and the reason beside it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KGcjxF1cNLcuwc3DAPcnfj

web/src/api.js

@@ -206,6 +206,8 @@ export const api = {
 
   sites: () => send('GET', '/api/sites'),
   createSite: (input) => send('POST', '/api/sites', input),
+  updateSite: (site, input) => send('PATCH', `/api/sites/${encodeURIComponent(site)}`, input),
+  deleteSite: (site) => send('DELETE', `/api/sites/${encodeURIComponent(site)}`),
 
   // The live arrivals feed. `cursor` is opaque and must be echoed back.
   arrivals: (params) => send('GET', '/api/visits' + qs(params)),