feat(inline-edit): add WYSIWYG inline dashboard editing mode

Replace the disconnected board edit page with inline editing directly
on the board view. Toggle with Ctrl+E or the Edit button. Features:

- Edit mode store with changeset accumulation and batch save
- Floating toolbar (save, discard, add section, board settings, exit)
- Widget hover overlays with edit/delete/drag controls
- Type-specific widget config panels for all 14 widget types
- Section inline editing (title, icon picker, delete)
- "+" buttons for adding widgets and sections inline
- Section-level drag-and-drop reordering via svelte-dnd-action
- Batch save API endpoint (single Prisma transaction)
- Board properties side panel with live theme/wallpaper preview
- Modal widget type picker with search filtering
- Icon picker component with visual grid and search
- Confirmation dialog modal for all destructive actions
- HTML format support for Note widget (in addition to markdown/text)
- Full i18n support (en + ru) for all new UI strings
- Legacy edit page banner linking to new inline mode

src/lib/components/section/Section.svelte

@@ -2,6 +2,8 @@
 	import SectionHeader from './SectionHeader.svelte';
 	import SectionCollapsible from './SectionCollapsible.svelte';
 	import WidgetGrid from '$lib/components/widget/WidgetGrid.svelte';
+	import { editMode } from '$lib/stores/editMode.svelte.js';
+	import type { CardSize } from '$lib/utils/constants.js';
 
 	interface WidgetData {
 		id: string;
@@ -20,8 +22,6 @@
 		} | null;
 	}
 
-	import type { CardSize } from '$lib/utils/constants.js';
-
 	interface SectionData {
 		id: string;
 		title: string;
@@ -58,17 +58,24 @@
 	let expanded = $state(section.isExpandedByDefault);
 </script>
 
-<div class="rounded-xl border border-border bg-card/30 shadow-sm">
+<div class="rounded-xl border border-border bg-card/30 shadow-sm {editMode.active ? 'ring-1 ring-primary/10' : ''}">
 	<SectionHeader
+		sectionId={section.id}
 		title={section.title}
 		icon={section.icon}
 		{expanded}
 		onToggle={() => (expanded = !expanded)}
+		widgetCount={section.widgets.length}
 	/>
 
 	<SectionCollapsible {expanded}>
 		<div class="px-4 pb-4">
-			<WidgetGrid widgets={section.widgets} {allApps} cardSize={effectiveCardSize} />
+			<WidgetGrid
+				widgets={section.widgets}
+				sectionId={section.id}
+				{allApps}
+				cardSize={effectiveCardSize}
+			/>
 		</div>
 	</SectionCollapsible>
 </div>