feat(iios): media sharing — presigned storage port + attachments on messages

Media the industry way: the DB stores a reference, bytes live behind a storage port.
- StoragePort + LocalDiskStorage (dev). MediaService presigns short-lived signed
  upload/download URLs (HS256 tokens) pointing at IIOS's own endpoints; the bytes
  never touch the kernel. Prod swaps STORAGE_PORT to S3/Supabase — same as auth.
- MediaController: presign-upload / PUT upload/:token (raw stream) / GET blob/:token /
  presign-download. Uploads are OPA-governed (iios.media.upload: 25 MB cap +
  image/video/audio/pdf/office allowlist); downloads are tenant-fenced by object key.
- send() + MessageDto carry an attachment (contentRef/mimeType/sizeBytes → generic
  MEDIA_REF/VOICE_REF/FILE_REF part; DTO exposes kind image|video|audio|file).

Tests: media.service.spec (6) — round-trip, oversize/type denied, oversized PUT
refused, tampered token rejected, tenant fence. Full suite 192 green. Verified live:
presign→upload→send→history→signed download round-trips the exact bytes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/iios-service/src/media/media.service.spec.ts

@@ -0,0 +1,72 @@
+import { describe, it, expect, beforeAll, afterAll, beforeEach } from 'vitest';
+import { PrismaClient } from '@prisma/client';
+import { PolicyDeniedError, type IiosPlatformPorts } from '@insignia/iios-contracts';
+import { makeFakePorts } from '@insignia/iios-testkit';
+import { resetDb } from '../test-utils/reset-db';
+import { ActorResolver, type MessagePrincipal } from '../identity/actor.resolver';
+import { DevOpaPort } from '../platform/dev-opa.port';
+import { LocalDiskStorage } from './local-disk.storage';
+import { MediaService } from './media.service';
+import type { PrismaService } from '../prisma/prisma.service';
+
+const url = process.env.DATABASE_URL ?? 'postgresql://iios:iios@localhost:5434/iios?schema=public';
+const prisma = new PrismaClient({ datasources: { db: { url } } });
+const asService = prisma as unknown as PrismaService;
+const ports = { ...makeFakePorts(), opa: new DevOpaPort() } as IiosPlatformPorts;
+const svc = () => new MediaService(new LocalDiskStorage(), ports, new ActorResolver(asService));
+const alice: MessagePrincipal = { userId: 'alice', orgId: 'org_demo', appId: 'portal-demo', displayName: 'Alice' };
+
+// point storage at an isolated temp dir for the test run
+process.env.MEDIA_DIR = process.env.MEDIA_DIR ?? '/tmp/iios-media-test';
+
+beforeAll(async () => { await prisma.$connect(); });
+afterAll(async () => { await prisma.$disconnect(); });
+beforeEach(async () => { await resetDb(prisma); });
+
+function tokenFrom(url: string): string {
+  return url.split('/').pop()!;
+}
+
+describe('MediaService (presigned local storage)', () => {
+  it('presign → PUT → presign-download → GET round-trips the bytes with mime + checksum', async () => {
+    const s = svc();
+    const bytes = Buffer.from('hello-image-bytes');
+    const { objectKey, uploadUrl } = await s.presignUpload(alice, { mime: 'image/png', sizeBytes: bytes.length });
+    expect(objectKey).toContain('/'); // scopeId/uuid
+
+    const put = await s.put(tokenFrom(uploadUrl), bytes);
+    expect(put.sizeBytes).toBe(bytes.length);
+    expect(put.checksumSha256).toHaveLength(64);
+
+    const { url } = await s.presignDownload(alice, objectKey, 'image/png');
+    const got = await s.get(tokenFrom(url));
+    expect(got.data.equals(bytes)).toBe(true);
+    expect(got.mime).toBe('image/png');
+  });
+
+  it('rejects an over-the-cap upload (OPA policy)', async () => {
+    await expect(svc().presignUpload(alice, { mime: 'image/png', sizeBytes: 26 * 1024 * 1024 })).rejects.toBeInstanceOf(PolicyDeniedError);
+  });
+
+  it('rejects a disallowed file type (OPA policy)', async () => {
+    await expect(svc().presignUpload(alice, { mime: 'application/x-msdownload', sizeBytes: 1000 })).rejects.toBeInstanceOf(PolicyDeniedError);
+  });
+
+  it('a PUT larger than the presigned size is refused', async () => {
+    const s = svc();
+    const { uploadUrl } = await s.presignUpload(alice, { mime: 'image/png', sizeBytes: 4 });
+    await expect(s.put(tokenFrom(uploadUrl), Buffer.from('way too many bytes'))).rejects.toThrow();
+  });
+
+  it('rejects a tampered / non-media token', async () => {
+    await expect(svc().get('not-a-real-token')).rejects.toThrow();
+    // an upload token cannot be used to download
+    const s = svc();
+    const { uploadUrl } = await s.presignUpload(alice, { mime: 'image/png', sizeBytes: 4 });
+    await expect(s.get(tokenFrom(uploadUrl))).rejects.toThrow();
+  });
+
+  it('tenant-fences downloads: an object outside my scope is forbidden', async () => {
+    await expect(svc().presignDownload(alice, 'some-other-scope/abc', 'image/png')).rejects.toThrow();
+  });
+});