feat(backend): implement v2 domain slice and live smoke

backend/command-api/src/contracts/commands/attendance.js

@@ -0,0 +1,14 @@
+import { z } from 'zod';
+
+export const attendanceCommandSchema = z.object({
+  assignmentId: z.string().uuid(),
+  sourceType: z.enum(['NFC', 'GEO', 'QR', 'MANUAL', 'SYSTEM']),
+  sourceReference: z.string().max(255).optional(),
+  nfcTagUid: z.string().max(255).optional(),
+  deviceId: z.string().max(255).optional(),
+  latitude: z.number().min(-90).max(90).optional(),
+  longitude: z.number().min(-180).max(180).optional(),
+  accuracyMeters: z.number().int().nonnegative().optional(),
+  capturedAt: z.string().datetime().optional(),
+  rawPayload: z.record(z.any()).optional(),
+});