Show parent > child location on detail pages, add location move

- Device/component detail pages show "Parent › Child" for locations
- Device list cards show full location path
- Location edit form now includes a Parent selector to move locations
  between parents or make them top-level
- Prevents setting a location as its own parent

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

src/routes/(app)/locations/+page.server.ts

@@ -73,11 +73,15 @@ export const actions: Actions = {
 		const id = formData.get('id') as string;
 		const name = (formData.get('name') as string)?.trim();
 		const description = (formData.get('description') as string)?.trim();
+		const parentId = (formData.get('parentId') as string) || null;
 		if (!name) return fail(400, { error: 'Name is required' });
 
+		// Prevent setting self as parent
+		if (parentId === id) return fail(400, { error: 'Cannot set location as its own parent' });
+
 		await db
 			.update(locations)
-			.set({ name, description: description || null, updatedAt: new Date() })
+			.set({ name, description: description || null, parentId, updatedAt: new Date() })
 			.where(eq(locations.id, id));
 		return { renamed: true };
 	},