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]/edit/+page.svelte

@@ -4,6 +4,7 @@
 	import { enhance } from '$app/forms';
 	import { invalidateAll } from '$app/navigation';
 	import DraggableBoard from '$lib/components/board/DraggableBoard.svelte';
+	import BoardAccessControl from '$lib/components/board/BoardAccessControl.svelte';
 	import { WidgetType } from '$lib/utils/constants.js';
 
 	let { data }: { data: PageData } = $props();
@@ -161,15 +162,6 @@
 							/>
 							{$t('board.default_board')}
 						</label>
-						<label class="flex items-center gap-2 text-sm text-foreground">
-							<input
-								type="checkbox"
-								name="isGuestAccessible"
-								checked={data.board.isGuestAccessible}
-								class="h-4 w-4 rounded border-input accent-primary"
-							/>
-							{$t('board.guest_accessible')}
-						</label>
 					</div>
 				</div>
 				<div class="mt-4">
@@ -183,6 +175,68 @@
 			</form>
 		</section>
 
+		<!-- Guest Access -->
+		<section class="mb-8 rounded-xl border border-border bg-card p-6 shadow-sm">
+			<h2 class="mb-4 text-lg font-semibold text-card-foreground">{$t('board.guest_access_title')}</h2>
+			<div class="rounded-lg border border-border bg-muted/30 p-4">
+				<form method="POST" action="?/updateBoard" use:enhance>
+					<input type="hidden" name="name" value={data.board.name} />
+					<input type="hidden" name="isDefault" value={data.board.isDefault ? 'on' : ''} />
+					<label class="flex items-start gap-3 text-sm text-foreground">
+						<input
+							type="checkbox"
+							name="isGuestAccessible"
+							checked={data.board.isGuestAccessible}
+							class="mt-0.5 h-4 w-4 rounded border-input accent-primary"
+						/>
+						<div>
+							<span class="font-medium">{$t('board.guest_accessible')}</span>
+							<p class="mt-1 text-xs text-muted-foreground">{$t('board.guest_access_description')}</p>
+							{#if data.board.isGuestAccessible}
+								<p class="mt-1 flex items-center gap-1 text-xs text-green-500">
+									<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+										<circle cx="12" cy="12" r="10" />
+										<line x1="2" y1="12" x2="22" y2="12" />
+										<path d="M12 2a15.3 15.3 0 0 1 4 10 15.3 15.3 0 0 1-4 10 15.3 15.3 0 0 1-4-10 15.3 15.3 0 0 1 4-10z" />
+									</svg>
+									{$t('board.guest_access_enabled')}
+								</p>
+							{:else}
+								<p class="mt-1 flex items-center gap-1 text-xs text-muted-foreground">
+									<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+										<rect x="3" y="11" width="18" height="11" rx="2" ry="2" />
+										<path d="M7 11V7a5 5 0 0 1 10 0v4" />
+									</svg>
+									{$t('board.guest_access_disabled')}
+								</p>
+							{/if}
+						</div>
+					</label>
+					<div class="mt-3">
+						<button
+							type="submit"
+							class="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-primary-foreground transition-colors hover:bg-primary/90"
+						>
+							{$t('board.save')}
+						</button>
+					</div>
+				</form>
+			</div>
+		</section>
+
+		<!-- Permissions -->
+		{#if data.canManagePermissions}
+			<section class="mb-8 rounded-xl border border-border bg-card p-6 shadow-sm">
+				<h2 class="mb-4 text-lg font-semibold text-card-foreground">{$t('board.permissions_title')}</h2>
+				<p class="mb-4 text-sm text-muted-foreground">{$t('board.permissions_description')}</p>
+				<BoardAccessControl
+					boardId={data.board.id}
+					users={data.users}
+					groups={data.groups}
+				/>
+			</section>
+		{/if}
+
 		<!-- Sections with Drag-and-Drop -->
 		<section class="mb-8">
 			<div class="mb-4 flex items-center justify-between">