feat: generate and edit conversation images across runtimes

Add model-controlled image invocation and read-only runtime assignments. Route image tools through Main so accepted operations retain their originating conversation when chat runtimes change, with saved references, cancellation, and manual recovery.

Keep Node hashing outside browser-shared contracts to restore production builds. Validation includes the production build, typecheck, lint, focused regressions, real Host transport checks, and two successful real image requests. Full UI-driven runtime switching acceptance remains documented as pending.

Release note: 开启图片模型的会话调用后，聊天助手可调用图片生成与编辑工具，Runtime 分配自动管理。图片成果保存在原会话，可继续修改，并独立显示生成状态和取消入口。

src/main/runtime-settings-store.test.ts

@@ -80,6 +80,57 @@ afterEach(async () => {
 })
 
 describe('RuntimeSettingsStore', () => {
+  it('round-trips conversation image settings and retains unavailable defaults without resolving credentials', async () => {
+    const { store, filePath } = await createStore()
+    const initial = await store.getPublicSettings()
+    expect(initial.modelProfiles[0]?.allowConversationInvocation).toBe(false)
+    expect(initial.defaultImageModelProfileId).toBeUndefined()
+    const imageId = '00000000-0000-4000-8000-000000000099'
+    const text = {
+      id: initial.modelProfiles[0]!.id, name: 'Text',
+      baseUrl: 'https://example.com', modelName: 'text',
+      protocol: 'openai-chat-completions' as const,
+      authentication: 'api-key' as const,
+      imageGenerationQuality: 'auto' as const,
+      apiKey: { action: 'keep' as const }
+    }
+    const image = {
+      ...text, id: imageId, name: 'Image model',
+      protocol: 'openai-images-generations' as const,
+      allowConversationInvocation: true,
+      apiKey: { action: 'replace' as const, value: 'image-secret' }
+    }
+    const input = settings({ modelProfiles: [text, image], defaultModelProfileId: text.id, defaultImageModelProfileId: imageId })
+    await store.update(runtimeSettingsInputSchema.parse(input))
+    const reloaded = new RuntimeSettingsStore(filePath, cipher, {})
+    expect((await reloaded.getPublicSettings()).modelProfiles[1]).toMatchObject({ allowConversationInvocation: true, apiKeyConfigured: true })
+    expect((await reloaded.getResolvedSettings()).defaultImageModelProfileId).toBe(imageId)
+    expect((await reloaded.getResolvedSettings()).modelProfiles[1]).toMatchObject({ allowConversationInvocation: true, apiKey: 'image-secret' })
+    expect((await reloaded.getPublicSettings()).configured?.modelProfiles[1]?.allowConversationInvocation).toBe(true)
+    const decrypt = vi.fn(() => { throw new Error('Credential unavailable') })
+    const credentialFree = new RuntimeSettingsStore(filePath, { ...cipher, decrypt }, {})
+    expect(await credentialFree.getSavedModelProfiles()).toEqual([
+      { id: text.id, name: text.name, protocol: text.protocol, allowConversationInvocation: false },
+      { id: imageId, name: image.name, protocol: image.protocol, allowConversationInvocation: true }
+    ])
+    expect(decrypt).not.toHaveBeenCalled()
+    await reloaded.update(settings())
+    expect((await reloaded.getSavedModelProfiles())[1]?.allowConversationInvocation).toBe(true)
+    expect((await reloaded.getPublicSettings()).defaultImageModelProfileId).toBe(imageId)
+    const disabled = await reloaded.update({ ...input, modelProfiles: [text, { ...image, allowConversationInvocation: false, apiKey: { action: 'keep' } }] })
+    expect(disabled.defaultImageModelProfileId).toBe(imageId)
+    expect(disabled.modelProfiles[1]).toMatchObject({ allowConversationInvocation: false, apiKeyConfigured: true })
+    const removed = await reloaded.update({ ...input, modelProfiles: [text] })
+    expect(removed.defaultImageModelProfileId).toBe(imageId)
+    expect((await new RuntimeSettingsStore(filePath, cipher, {}).getPublicSettings()).defaultImageModelProfileId).toBe(imageId)
+    expect((await reloaded.update({ ...input, modelProfiles: [text], defaultImageModelProfileId: null })).defaultImageModelProfileId).toBeNull()
+  })
+
+  it('rejects malformed conversation image settings', () => {
+    expect(runtimeSettingsInputSchema.safeParse(settings({ defaultImageModelProfileId: 'not-a-uuid' })).success).toBe(false)
+    expect(runtimeSettingsInputSchema.safeParse({ ...settings(), modelProfiles: [{ id: '00000000-0000-4000-8000-000000000001', name: 'Image', baseUrl: 'https://example.com', modelName: 'image', protocol: 'openai-images-generations', authentication: 'none', imageGenerationQuality: 'auto', apiKey: { action: 'keep' }, allowConversationInvocation: 'true' }] }).success).toBe(false)
+  })
+
   it('defaults to automatic Execute tool authorization and preserves an explicitly saved deny policy', async () => {
     const { store, filePath } = await createStore()
     await expect(store.getPublicSettings()).resolves.toMatchObject({ toolApproval: 'always' })