feat(phase2): localization EN/RU + additional widget types

- Add svelte-i18n with 224 translation keys (English + Russian)
- Language switcher in header (EN/RU toggle, persists to localStorage)
- Extract all hardcoded strings from 37 component/page files
- Add 4 new widget types: Bookmark, Note (markdown), Embed (iframe), Status
- WidgetRenderer dispatches by type, WidgetGrid supports full-width widgets
- Type-specific config forms in board editor
- Install marked for markdown rendering

src/lib/components/app/AppForm.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { t } from 'svelte-i18n';
 	import { superForm, type SuperValidated } from 'sveltekit-superforms';
 	import type { z } from 'zod';
 	import type { createAppSchema } from '$lib/utils/validators.js';
@@ -24,7 +25,7 @@
 	<div class="grid grid-cols-1 gap-4 sm:grid-cols-2">
 		<div>
 			<label for="name" class="mb-1 block text-sm font-medium text-card-foreground">
-				Name <span class="text-destructive">*</span>
+				{$t('app.name')} <span class="text-destructive">{$t('common.required')}</span>
 			</label>
 			<input
 				id="name"
@@ -32,7 +33,7 @@
 				type="text"
 				bind:value={$form.name}
 				class="w-full rounded-md border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring"
-				placeholder="My Application"
+				placeholder={$t('app.name_placeholder')}
 			/>
 			{#if $errors.name}
 				<p class="mt-1 text-sm text-destructive">{$errors.name[0]}</p>
@@ -41,7 +42,7 @@
 
 		<div>
 			<label for="url" class="mb-1 block text-sm font-medium text-card-foreground">
-				URL <span class="text-destructive">*</span>
+				{$t('app.url')} <span class="text-destructive">{$t('common.required')}</span>
 			</label>
 			<input
 				id="url"
@@ -49,7 +50,7 @@
 				type="url"
 				bind:value={$form.url}
 				class="w-full rounded-md border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring"
-				placeholder="https://my-app.local:8080"
+				placeholder={$t('app.url_placeholder')}
 			/>
 			{#if $errors.url}
 				<p class="mt-1 text-sm text-destructive">{$errors.url[0]}</p>
@@ -59,7 +60,7 @@
 
 	<div>
 		<label for="description" class="mb-1 block text-sm font-medium text-card-foreground">
-			Description
+			{$t('app.description')}
 		</label>
 		<input
 			id="description"
@@ -67,14 +68,14 @@
 			type="text"
 			bind:value={$form.description}
 			class="w-full rounded-md border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring"
-			placeholder="Brief description of this app"
+			placeholder={$t('app.description_placeholder')}
 		/>
 	</div>
 
 	<div class="grid grid-cols-1 gap-4 sm:grid-cols-2">
 		<div>
 			<label for="category" class="mb-1 block text-sm font-medium text-card-foreground">
-				Category
+				{$t('app.category')}
 			</label>
 			<input
 				id="category"
@@ -82,13 +83,13 @@
 				type="text"
 				bind:value={$form.category}
 				class="w-full rounded-md border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring"
-				placeholder="e.g. Media, Monitoring, Storage"
+				placeholder={$t('app.category_placeholder')}
 			/>
 		</div>
 
 		<div>
 			<label for="tags" class="mb-1 block text-sm font-medium text-card-foreground">
-				Tags
+				{$t('app.tags')}
 			</label>
 			<input
 				id="tags"
@@ -96,7 +97,7 @@
 				type="text"
 				bind:value={$form.tags}
 				class="w-full rounded-md border border-input bg-background px-3 py-2 text-sm text-foreground placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring"
-				placeholder="Comma-separated tags"
+				placeholder={$t('app.tags_placeholder')}
 			/>
 		</div>
 	</div>
@@ -117,7 +118,7 @@
 		onclick={() => (showAdvanced = !showAdvanced)}
 		class="text-sm text-muted-foreground hover:text-foreground"
 	>
-		{showAdvanced ? 'Hide' : 'Show'} Healthcheck Settings
+		{showAdvanced ? $t('app.healthcheck_hide') : $t('app.healthcheck_show')} {$t('app.healthcheck_toggle')}
 	</button>
 
 	{#if showAdvanced}
@@ -131,7 +132,7 @@
 					class="rounded border-input"
 				/>
 				<label for="healthcheckEnabled" class="text-sm text-card-foreground">
-					Enable Healthcheck
+					{$t('app.healthcheck_enabled')}
 				</label>
 			</div>
 
@@ -142,7 +143,7 @@
 							for="healthcheckMethod"
 							class="mb-1 block text-sm font-medium text-card-foreground"
 						>
-							Method
+							{$t('app.healthcheck_method')}
 						</label>
 						<select
 							id="healthcheckMethod"
@@ -160,7 +161,7 @@
 							for="healthcheckExpectedStatus"
 							class="mb-1 block text-sm font-medium text-card-foreground"
 						>
-							Expected Status
+							{$t('app.healthcheck_expected_status')}
 						</label>
 						<input
 							id="healthcheckExpectedStatus"
@@ -178,7 +179,7 @@
 							for="healthcheckTimeout"
 							class="mb-1 block text-sm font-medium text-card-foreground"
 						>
-							Timeout (ms)
+							{$t('app.healthcheck_timeout')}
 						</label>
 						<input
 							id="healthcheckTimeout"
@@ -198,7 +199,7 @@
 						for="healthcheckInterval"
 						class="mb-1 block text-sm font-medium text-card-foreground"
 					>
-						Interval (seconds)
+						{$t('app.healthcheck_interval')}
 					</label>
 					<input
 						id="healthcheckInterval"
@@ -221,9 +222,9 @@
 			class="rounded-md bg-primary px-6 py-2 text-sm font-medium text-primary-foreground hover:bg-primary/90 focus:outline-none focus:ring-2 focus:ring-ring disabled:cursor-not-allowed disabled:opacity-50"
 		>
 			{#if $submitting}
-				Saving...
+				{$t('app.saving')}
 			{:else}
-				Save App
+				{$t('app.save')}
 			{/if}
 		</button>
 	</div>