feat(phase3): import/export, sparklines, user theme overrides

- JSON import/export with conflict resolution (skip/overwrite) + admin UI
- Ping history sparklines on AppWidget and AppCard (24h, 288 points)
- Hourly cleanup job for old AppStatus records
- User theme preferences (hue, saturation, mode, background, locale)
- Settings page with ThemeCustomizer (sliders, toggles, live preview)
- Prisma migration for user preference fields
- i18n translations for all new strings (EN/RU)

src/lib/utils/validators.ts

@@ -181,6 +181,71 @@ export const createPermissionSchema = z.object({
 	level: z.enum([PermissionLevel.VIEW, PermissionLevel.EDIT, PermissionLevel.ADMIN])
 });
 
+// --- Import/Export ---
+
+const importAppSchema = z.object({
+	name: z.string().min(1).max(200),
+	url: z.string().url(),
+	icon: z.string().max(500).nullable(),
+	iconType: z.string().max(50),
+	description: z.string().max(1000).nullable(),
+	category: z.string().max(100).nullable(),
+	tags: z.string().max(500),
+	healthcheckEnabled: z.boolean(),
+	healthcheckInterval: z.number().int().min(30).max(86400),
+	healthcheckMethod: z.string(),
+	healthcheckExpectedStatus: z.number().int().min(100).max(599),
+	healthcheckTimeout: z.number().int().min(1000).max(30000)
+});
+
+const importWidgetSchema = z.object({
+	type: z.string().min(1),
+	order: z.number().int().min(0),
+	config: z.string(),
+	appName: z.string().nullable()
+});
+
+const importSectionSchema = z.object({
+	title: z.string().min(1).max(200),
+	icon: z.string().max(500).nullable(),
+	order: z.number().int().min(0),
+	isExpandedByDefault: z.boolean(),
+	widgets: z.array(importWidgetSchema)
+});
+
+const importBoardSchema = z.object({
+	name: z.string().min(1).max(200),
+	icon: z.string().max(500).nullable(),
+	description: z.string().max(1000).nullable(),
+	isDefault: z.boolean(),
+	isGuestAccessible: z.boolean(),
+	backgroundConfig: z.string().nullable(),
+	sections: z.array(importSectionSchema)
+});
+
+const importGroupSchema = z.object({
+	name: z.string().min(1).max(100),
+	description: z.string().max(500).nullable(),
+	isDefault: z.boolean()
+});
+
+const importSettingsSchema = z.object({
+	authMode: z.string().optional(),
+	registrationEnabled: z.boolean().optional(),
+	defaultTheme: z.string().optional(),
+	defaultPrimaryColor: z.string().optional(),
+	healthcheckDefaults: z.string().optional()
+});
+
+export const importDataSchema = z.object({
+	version: z.string(),
+	exportedAt: z.string(),
+	apps: z.array(importAppSchema),
+	boards: z.array(importBoardSchema),
+	groups: z.array(importGroupSchema),
+	settings: importSettingsSchema
+});
+
 // --- System Settings ---
 
 export const updateSystemSettingsSchema = z.object({