Add checklist templates with import into devices

- checklist_templates and template_items tables for reusable checklists
- /checklists page: create/edit/delete templates with ordered items
- "Import" button on device detail imports a template as a new checklist
  with all items copied (unchecked)
- Sidebar nav item for Checklists between Locations and Gallery

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/lib/server/db/schema.ts

@@ -195,6 +195,29 @@ export const installationLog = pgTable(
 	]
 );
 
+// ─── Checklist Templates ────────────────────────────────────────────
+
+export const checklistTemplates = pgTable('checklist_templates', {
+	id: uuid('id').defaultRandom().primaryKey(),
+	title: text('title').notNull(),
+	description: text('description'),
+	createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
+	updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow().notNull()
+});
+
+export const templateItems = pgTable(
+	'template_items',
+	{
+		id: uuid('id').defaultRandom().primaryKey(),
+		templateId: uuid('template_id')
+			.notNull()
+			.references(() => checklistTemplates.id, { onDelete: 'cascade' }),
+		text: text('text').notNull(),
+		sortOrder: integer('sort_order').default(0).notNull()
+	},
+	(table) => [index('template_items_template_idx').on(table.templateId)]
+);
+
 // ─── Device Checklists ──────────────────────────────────────────────
 
 export const deviceChecklists = pgTable(