feat(federation): shared epoch types + getInstanceId()

packages/server/src/routes/instance.test.ts

@@ -53,9 +53,11 @@ beforeEach(async () => {
 
   // Seed the singleton instance_settings row mirroring ensureDefaults() —
   // tests don't run the boot-time helper, so we insert manually with the
-  // schema-default values for the new federatedRegistrationOpen column.
+  // schema-default values for the new federatedRegistrationOpen column plus
+  // the persistent epoch (instanceId) that ensureDefaults mints on boot.
   testDb.insert(schema.instanceSettings).values({
     id: 1,
+    instanceId: '123e4567-e89b-12d3-a456-426614174000',
     updatedAt: Date.now(),
   }).run();
 
@@ -94,5 +96,8 @@ describe('GET /api/instance/info', () => {
     expect(typeof body.sourceCodeUrl).toBe('string');
     expect(body.sourceCodeUrl).toMatch(/^https?:\/\//);
     expect(body.commit === null || typeof body.commit === 'string').toBe(true);
+    // Persistent per-instance epoch (incarnation UUID) is always advertised.
+    expect(typeof body.instanceId).toBe('string');
+    expect(body.instanceId).toMatch(/^[0-9a-f-]{36}$/);
   });
 });

packages/server/src/routes/instance.ts

@@ -2,6 +2,7 @@ import type { FastifyInstance } from 'fastify';
 import { eq } from 'drizzle-orm';
 import { getDb, schema } from '../db/index.js';
 import { config } from '../config.js';
+import { getInstanceId } from '../utils/federationEpoch.js';
 import type { InstanceInfoResponse } from '@backspace/shared';
 
 const BACKSPACE_VERSION = '1.0.0';
@@ -23,6 +24,7 @@ export async function instanceRoutes(app: FastifyInstance): Promise<void> {
       version: BACKSPACE_VERSION,
       registrationOpen,
       federatedRegistrationOpen: settings?.federatedRegistrationOpen === 1,
+      instanceId: getInstanceId(),
       // AGPL-3.0 § 13: advertise the source of the running version to every
       // network user (and federated peer) — public/unauthenticated by design.
       sourceCodeUrl: config.sourceCodeUrl,