feat(phase2): per-board access control UI

- BoardAccessControl component with user/group autocomplete
- BoardShareDialog modal with copy link, guest toggle, quick add
- Board permissions REST API (GET/POST/DELETE)
- Access indicators on BoardCard (lock, globe, shared icons)
- Guest access toggle in board editor with status preview
- Enhanced PermissionEditor with search autocomplete
- i18n translations for all new strings (EN/RU)

src/routes/boards/[boardId]/+page.server.ts

@@ -3,6 +3,8 @@ import type { PageServerLoad } from './$types.js';
 import * as boardService from '$lib/server/services/boardService.js';
 import * as appService from '$lib/server/services/appService.js';
 import * as permissionService from '$lib/server/services/permissionService.js';
+import * as userService from '$lib/server/services/userService.js';
+import * as groupService from '$lib/server/services/groupService.js';
 import { EntityType, PermissionLevel, UserRole } from '$lib/utils/constants.js';
 import { isBoardGuestAccessible } from '$lib/server/middleware/guestAccess.js';
 
@@ -54,7 +56,26 @@ export const load: PageServerLoad = async ({ params, locals }) => {
 			}
 		}
 
-		return { board, canEdit, allApps };
+		// Load users and groups for the share dialog (only if user can edit)
+		let users: { id: string; name: string }[] = [];
+		let groups: { id: string; name: string }[] = [];
+
+		if (canEdit) {
+			const [allUsers, allGroups] = await Promise.all([
+				userService.findAll(),
+				groupService.findAll()
+			]);
+			users = allUsers.map((u) => ({
+				id: u.id,
+				name: u.displayName || u.email
+			}));
+			groups = allGroups.map((g) => ({
+				id: g.id,
+				name: g.name
+			}));
+		}
+
+		return { board, canEdit, allApps, users, groups };
 	} catch (err) {
 		const message = err instanceof Error ? err.message : 'Board not found';
 		if (message.includes('not found')) {