fix(gui): harden multimodal image attachments

scripts/test-invariants.ts

@@ -8,6 +8,13 @@
 import { expect } from 'vitest'
 import { RegistryService } from 'cordis'
 import type { Context, Plugin } from 'cordis'
+import { AttachmentStore } from '@deepseek-ai/dsh-attachment'
+import type {
+  ImageAttachmentLimits,
+  ImageAttachmentRef,
+  SaveImageAttachment,
+  StoredImageAttachment,
+} from '@deepseek-ai/dsh-attachment'
 import InvariantService from '@deepseek-ai/dsh-invariants'
 
 declare global {
@@ -78,6 +85,25 @@ export function usesManualInvariantTree(testPath: string): boolean {
 }
 
 const ALL_COMPANION_TESTS = ['/scripts/test-invariants.spec.ts'] as const
+const ATTACHMENT_COMPANION = '../packages/attachment/attachment-local/src/invariant.ts'
+
+class TestAttachmentStore extends AttachmentStore {
+  readonly imageLimits: ImageAttachmentLimits = {
+    maxImageBytes: 1,
+    maxImagesPerMessage: 1,
+    maxMessageImageBytes: 1,
+    maxImagePixels: 1,
+    mediaTypes: ['image/png'],
+  }
+
+  saveImage(_input: SaveImageAttachment): Promise<ImageAttachmentRef> {
+    return Promise.reject(new Error('test invariant attachment store does not save images'))
+  }
+
+  readImage(_ref: ImageAttachmentRef): Promise<StoredImageAttachment> {
+    return Promise.reject(new Error('test invariant attachment store does not read images'))
+  }
+}
 
 /**
  * Select the package companions that an ordinary test root must register.
@@ -115,6 +141,7 @@ function startInvariantHost(root: Context): InvariantHost {
   mount(InvariantService, { enabled: true })
   const testPath = expect.getState().testPath ?? ''
   const companionPaths = testInvariantCompanionPaths(testPath)
+  if (companionPaths.includes(ATTACHMENT_COMPANION)) mount(TestAttachmentStore)
   for (const path of companionPaths) {
     const companion = testInvariantCompanions[path]
     if (companion === undefined) {