feat: add onAvatarResolve plugin hook

lib/plugin-api.ts

@@ -22,7 +22,7 @@ import {
   taskHooks, templateHooks, smimeHooks, vacationHooks,
   uiHooks, themeHooks, toastHooks, dragDropHooks,
   keyboardHooks, appLifecycleHooks, accountSecurityHooks,
-  sidebarAppHooks,
+  sidebarAppHooks, avatarHooks,
 } from './plugin-hooks';
 import { toast as appToast } from '@/stores/toast-store';
 import { useAuthStore } from '@/stores/auth-store';
@@ -314,6 +314,8 @@ export interface PluginHooksAPI {
   onSidebarAppOpen: (handler: (...args: unknown[]) => unknown) => Disposable;
   onSidebarAppClose: (handler: (...args: unknown[]) => unknown) => Disposable;
   onSidebarAppChange: (handler: (...args: unknown[]) => unknown) => Disposable;
+  // Avatar
+  onAvatarResolve: (handler: (...args: unknown[]) => unknown) => Disposable;
 }
 
 // --- Permission mapping for hooks ----------------------------
@@ -417,6 +419,8 @@ const HOOK_PERMISSIONS: Record<string, Permission> = {
   // Sidebar Apps
   onSidebarAppOpen: 'ui:observe', onSidebarAppClose: 'ui:observe',
   onSidebarAppChange: 'ui:observe',
+  // Avatar
+  onAvatarResolve: 'email:read',
 };
 
 // Map hook names → actual HookBus instances
@@ -463,6 +467,8 @@ const HOOK_BUSES: Record<string, { register: (pluginId: string, handler: (...arg
   ...Object.fromEntries(Object.entries(accountSecurityHooks)),
   // Sidebar Apps
   ...Object.fromEntries(Object.entries(sidebarAppHooks)),
+  // Avatar
+  ...Object.fromEntries(Object.entries(avatarHooks)),
 };
 
 // --- Slot registration bridge --------------------------------

lib/plugin-hooks.ts

@@ -399,6 +399,13 @@ export const sidebarAppHooks = {
   onSidebarAppChange: new HookBus(),
 };
 
+// §7.21 Avatar Hooks
+// Transform hook: handlers receive (currentUrl: string | null, context: { email: string; name?: string })
+// and return a URL string to use as the avatar, or undefined/null to pass through to the next handler.
+export const avatarHooks = {
+  onAvatarResolve: new HookBus(),
+};
+
 // ─── Aggregate: remove all handlers for a plugin across all buses ───
 
 const allHookGroups = [
@@ -407,6 +414,7 @@ const allHookGroups = [
   taskHooks, templateHooks, smimeHooks, vacationHooks,
   uiHooks, themeHooks, toastHooks, dragDropHooks,
   keyboardHooks, appLifecycleHooks, accountSecurityHooks, sidebarAppHooks,
+  avatarHooks,
 ];
 
 export function removeAllPluginHooks(pluginId: string): void {