feat: add plugin ui.rerenderEmail API and restyle read-receipt banner

lib/plugin-sandbox/host-api.ts

@@ -56,6 +56,7 @@ const PERM_PER_METHOD: Record<string, Permission | null> = {
   'ui.confirm': null,
   'ui.alert': null,
   'ui.prompt': null,
+  'ui.rerenderEmail': null,
   'ui.openExternalUrl': null,
 };
 
@@ -410,6 +411,14 @@ export async function dispatchApiCall(
         fields,
       });
     }
+    case 'ui.rerenderEmail': {
+      // Re-run the onRenderEmailBody hook for the currently open message. Used
+      // by crypto plugins after they change decryption state (e.g. an S/MIME key
+      // was just unlocked) so the body re-decrypts without a full reload — which
+      // would wipe the in-memory session keys.
+      window.dispatchEvent(new CustomEvent('plugin:rerender-email'));
+      return undefined;
+    }
     case 'ui.openExternalUrl': {
       const url = String(args[0] ?? '');
       // Only http(s) - the sandbox should not be able to navigate the host

lib/plugin-sandbox/protocol.ts

@@ -244,7 +244,7 @@ export const API_METHODS = [
   'jmap.fetchBlob', 'jmap.sendRaw',
   'admin.getConfig', 'admin.getAllConfig', 'admin.setConfig', 'admin.deleteConfig',
   'toast.success', 'toast.error', 'toast.info', 'toast.warning',
-  'ui.confirm', 'ui.alert', 'ui.prompt', 'ui.openExternalUrl',
+  'ui.confirm', 'ui.alert', 'ui.prompt', 'ui.rerenderEmail', 'ui.openExternalUrl',
 ] as const;
 
 export type ApiMethod = (typeof API_METHODS)[number];

lib/plugin-sandbox/runtime.tsx

@@ -223,6 +223,9 @@ function buildPluginApi(manifest: PluginManifest) {
         cancelLabel?: string;
         fields?: Array<{ name: string; label: string; type?: 'text' | 'password'; placeholder?: string; required?: boolean }>;
       }) => callApi('ui.prompt', [opts], 0) as Promise<Record<string, string> | null>,
+      /** Re-runs the onRenderEmailBody hook for the open message (e.g. after a
+       *  crypto plugin unlocks a key) so its body re-renders without a reload. */
+      rerenderEmail: () => callApi('ui.rerenderEmail', []) as Promise<void>,
       /** Opens an http/https URL in a new tab via host `window.open`. */
       openExternalUrl: (url: string, target?: string) =>
         callApi('ui.openExternalUrl', [url, target]) as Promise<void>,