Merge remote-tracking branch 'origin/master' into worktree/web-theme-settings-integration-fde706

# Conflicts:
#	docs/module-graph.i18n.yaml
#	docs/module-graph.md
#	docs/module-graph.zh.md
#	packages/client/ui-conversation/package.json
#	pnpm-lock.yaml

packages/client/test-runtime/src/sessions.ts

@@ -1,5 +1,6 @@
 /** Test-owned sessions face: the SlotsService host contract over declarative fixtures. */
 import type { Context } from 'cordis'
+import type { AttachmentIdType } from '@deepseek-ai/dsh-attachment'
 import { createScope, scopeOf, SessionProvideChannel } from '@deepseek-ai/dsh-client-runtime/client'
 import { createSnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
 import type {
@@ -88,6 +89,15 @@ export class FixtureSession implements SessionFace {
     throw new Error(`test session "${this.sessionId}": prompt is not stubbed — supply it on the fixture's session face`)
   }
 
+  /**
+   * Fail-loud stub; supply `readAttachment` on the fixture's session face to exercise it.
+   * @param _attachmentId - opaque durable attachment id.
+   * @returns never — always throws.
+   */
+  readAttachment(_attachmentId: AttachmentIdType): never {
+    throw new Error(`test session "${this.sessionId}": readAttachment is not stubbed — supply it on the fixture's session face`)
+  }
+
   /**
    * Fail-loud stub; supply `updateQueue` on the fixture's session face to exercise it.
    * @returns never — always throws.