feat(mail): in-app attachments on internal mail + surface media parts in thread reads

- MailInternalDto accepts attachments[]; deposit() stores each as a media
  part (image/video→MEDIA_REF, audio→VOICE_REF, else FILE_REF)
- ingest now persists part sizeBytes; contract + DTO carry it
- threads.getMessages returns mimeType + sizeBytes so mail readers can
  render inline images / file chips
- test: internal mail stores an image attachment as a MEDIA_REF part

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/iios-service/src/interactions/ingest.dto.ts

@@ -1,6 +1,7 @@
 import { Type } from 'class-transformer';
 import {
   IsArray,
+  IsInt,
   IsISO8601,
   IsObject,
   IsOptional,
@@ -40,6 +41,7 @@ class PartDto {
   @IsOptional() @IsString() bodyText?: string;
   @IsOptional() @IsString() contentRef?: string;
   @IsOptional() @IsString() mimeType?: string;
+  @IsOptional() @IsInt() sizeBytes?: number;
 }
 
 /** Validates the POST /v1/interactions/ingest body (conforms to IngestInteractionRequest). */

packages/iios-service/src/interactions/ingest.service.ts

@@ -178,6 +178,7 @@ export class IngestService {
             bodyText: p.bodyText,
             contentRef: p.contentRef,
             mimeType: p.mimeType,
+            sizeBytes: p.sizeBytes != null ? BigInt(p.sizeBytes) : undefined,
           })),
         });
 

packages/iios-service/src/mail/mail.controller.ts

@@ -22,6 +22,7 @@ export class MailController {
       vars: body.vars ?? {},
       ...(body.locale ? { locale: body.locale } : {}),
       idempotencyKey: body.idempotencyKey,
+      ...(body.attachments && body.attachments.length > 0 ? { attachments: body.attachments } : {}),
     });
   }
 

packages/iios-service/src/mail/mail.dto.ts

@@ -7,6 +7,7 @@ export class AttachmentDto {
   @IsOptional() @IsString() filename?: string;
   @IsString() @IsNotEmpty() contentRef!: string;
   @IsOptional() @IsString() mimeType?: string;
+  @IsOptional() @IsInt() sizeBytes?: number;
 }
 
 /** POST /v1/mail/internal — app-to-app mail (no SMTP). Provide EITHER `key` OR `inline`. */
@@ -19,6 +20,8 @@ export class MailInternalDto {
   @IsOptional() @IsObject() vars?: Record<string, unknown>;
   @IsOptional() @IsString() locale?: string;
   @IsString() @IsNotEmpty() idempotencyKey!: string;
+  /** In-app attachment refs — stored as message parts so the recipient's inbox can render them. */
+  @IsOptional() @IsArray() @ValidateNested({ each: true }) @Type(() => AttachmentDto) attachments?: AttachmentDto[];
 }
 
 /** POST /v1/mail/send — external email via SMTP + optional in-app mirror for a registered recipient. */

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

@@ -66,6 +66,20 @@ describe('MailService.postInternal', () => {
     expect(aliceThreads.map((t) => t.threadId)).toContain(res.threadId);
   });
 
+  it('stores an in-app attachment as a media part alongside the body', async () => {
+    const res = await mail().postInternal(alice, {
+      source: inline, recipientUserId: 'bob', idempotencyKey: 'int:att',
+      attachments: [{ filename: 'roof.png', contentRef: 'scope/roof.png', mimeType: 'image/png', sizeBytes: 2048 }],
+    });
+    const interaction = await prisma.iiosInteraction.findUniqueOrThrow({ where: { id: res.interactionId }, include: { parts: true } });
+    const file = interaction.parts.find((p) => p.contentRef);
+    expect(file).toBeDefined();
+    expect(file!.kind).toBe('MEDIA_REF'); // image/* → MEDIA_REF
+    expect(file!.contentRef).toBe('scope/roof.png');
+    expect(file!.mimeType).toBe('image/png');
+    expect(file!.sizeBytes != null ? Number(file!.sizeBytes) : null).toBe(2048);
+  });
+
   it('is idempotent per key — a replay reuses the same thread, no duplicate interaction', async () => {
     const a = await mail().postInternal(alice, { source: inline, recipientUserId: 'bob', idempotencyKey: 'int:dup' });
     const b = await mail().postInternal(alice, { source: inline, recipientUserId: 'bob', idempotencyKey: 'int:dup' });

packages/iios-service/src/mail/mail.service.ts

@@ -20,12 +20,16 @@ export function contentToParts(content: RenderedContent): { subject?: string; pa
   return { ...(content.subject != null ? { subject: content.subject } : {}), parts };
 }
 
+export interface MailAttachment { filename?: string; contentRef: string; mimeType?: string; sizeBytes?: number }
+
 export interface PostInternalInput {
   source: TemplateSource;
   recipientUserId: string;
   vars?: Record<string, unknown>;
   locale?: string;
   idempotencyKey: string;
+  /** In-app attachment refs — stored as FILE message parts alongside the body. */
+  attachments?: MailAttachment[];
 }
 
 export interface SendExternalInput {
@@ -65,7 +69,7 @@ export class MailService {
 
   async postInternal(principal: MessagePrincipal, input: PostInternalInput): Promise<{ threadId: string; interactionId: string }> {
     const { content } = await this.templates.render(input.source, input.vars ?? {}, { channel: 'INTERNAL', ...(input.locale ? { locale: input.locale } : {}) });
-    return this.deposit(principal, input.recipientUserId, content, input.idempotencyKey, 'PORTAL');
+    return this.deposit(principal, input.recipientUserId, content, input.idempotencyKey, 'PORTAL', input.attachments);
   }
 
   async sendExternalWithMirror(principal: MessagePrincipal, input: SendExternalInput): Promise<{ commandId: string; mirror?: { threadId: string; interactionId: string } }> {
@@ -79,13 +83,21 @@ export class MailService {
     if (!input.mirrorToUserId) return { commandId: command.id };
 
     const { content } = await this.templates.render(input.source, input.vars ?? {}, { channel: 'EMAIL', ...(input.locale ? { locale: input.locale } : {}) });
-    const mirror = await this.deposit(principal, input.mirrorToUserId, content, `mirror:${input.idempotencyKey}`, 'EMAIL');
+    const mirror = await this.deposit(principal, input.mirrorToUserId, content, `mirror:${input.idempotencyKey}`, 'EMAIL', input.attachments);
     return { commandId: command.id, mirror };
   }
 
+  /** A stored media ref → a message part; kind follows the mime (image/video → MEDIA_REF, audio → VOICE_REF, else FILE_REF). */
+  private attachmentPart(a: MailAttachment): { kind: 'MEDIA_REF' | 'VOICE_REF' | 'FILE_REF'; bodyText?: string; contentRef: string; mimeType?: string; sizeBytes?: number } {
+    const mime = a.mimeType ?? '';
+    const kind = /^(image|video)\//.test(mime) ? 'MEDIA_REF' : /^audio\//.test(mime) ? 'VOICE_REF' : 'FILE_REF';
+    return { kind, ...(a.filename ? { bodyText: a.filename } : {}), contentRef: a.contentRef, ...(a.mimeType ? { mimeType: a.mimeType } : {}), ...(a.sizeBytes != null ? { sizeBytes: a.sizeBytes } : {}) };
+  }
+
   /** Ingest the rendered content as an EMAIL interaction on a per-email thread, visible to both parties. */
-  private async deposit(principal: MessagePrincipal, recipientUserId: string, content: RenderedContent, key: string, channelType: string): Promise<{ threadId: string; interactionId: string }> {
+  private async deposit(principal: MessagePrincipal, recipientUserId: string, content: RenderedContent, key: string, channelType: string, attachments?: MailAttachment[]): Promise<{ threadId: string; interactionId: string }> {
     const { subject, parts } = contentToParts(content);
+    const allParts = [...parts, ...(attachments ?? []).map((a) => this.attachmentPart(a))];
     const res = await this.ingest.ingest(
       {
         scope: { orgId: principal.orgId, appId: principal.appId, ...(principal.tenantId ? { tenantId: principal.tenantId } : {}) },
@@ -93,7 +105,7 @@ export class MailService {
         source: { handleKind: 'PORTAL_USER', externalId: principal.userId, ...(principal.displayName ? { displayName: principal.displayName } : {}) },
         kind: 'EMAIL',
         thread: { externalThreadId: key, ...(subject ? { subject } : {}) },
-        parts,
+        parts: allParts,
         occurredAt: new Date().toISOString(),
         providerEventId: key,
       },

packages/iios-service/src/threads/threads.service.ts

@@ -9,7 +9,7 @@ export interface ThreadMessage {
   actorId: string | null;
   kind: string;
   occurredAt: Date;
-  parts: Array<{ kind: string; bodyText: string | null; contentRef: string | null }>;
+  parts: Array<{ kind: string; bodyText: string | null; contentRef: string | null; mimeType: string | null; sizeBytes: number | null }>;
 }
 
 @Injectable()
@@ -39,7 +39,7 @@ export class ThreadsService {
         actorId: i.actorId,
         kind: i.kind,
         occurredAt: i.occurredAt,
-        parts: i.parts.map((p) => ({ kind: p.kind, bodyText: p.bodyText, contentRef: p.contentRef })),
+        parts: i.parts.map((p) => ({ kind: p.kind, bodyText: p.bodyText, contentRef: p.contentRef, mimeType: p.mimeType, sizeBytes: p.sizeBytes != null ? Number(p.sizeBytes) : null })),
       })),
     };
   }