refactor(client): isolate trajectory history

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

@@ -108,13 +108,6 @@ export class FixtureSession implements SessionFace {
     throw new Error(`test session "${this.sessionId}": loadOlder is not stubbed — supply it on the fixture's session face`)
   }
 
-  /**
-   * Fail-loud stub; supply `loadAllHistory` on the fixture's session face to exercise it.
-   * @returns never — always throws.
-   */
-  loadAllHistory(): never {
-    throw new Error(`test session "${this.sessionId}": loadAllHistory is not stubbed — supply it on the fixture's session face`)
-  }
 }
 
 /** One live test session: fixture-derived stores plus its minted scope state. */

packages/client/test-runtime/tests/runtime.spec.tsx

@@ -470,7 +470,6 @@ describe('fixture session face', () => {
     expect(() => bare.cancel()).toThrow(/cancel is not stubbed/)
     expect(() => bare.command()).toThrow(/command is not stubbed/)
     expect(() => bare.loadOlder()).toThrow(/loadOlder is not stubbed/)
-    expect(() => bare.loadAllHistory()).toThrow(/loadAllHistory is not stubbed/)
     await runtime.dispose()
   })