🎭 test: Run Mock E2E Suite Through createRun With In-Process Fake Model (#13508)

* 🎭 test: Run Mock E2E Suite Through createRun With In-Process Fake Model

Replace the standalone HTTP mock LLM server with an in-process fake model
injected into the real createRun -> Run.create pipeline via
run.Graph.overrideTestModel, so the mock suite exercises the agents
integration end-to-end without a live provider or a separate server.

- Bump @librechat/agents to 3.2.2 for the FakeChatModel/createFakeStreamingLLM exports
- Add an env-gated applyTestRunHook seam in packages/api createRun (no /api changes)
- Add e2e/setup/fake-model.js to drive default replies + the skill-authoring tool-call flow
- Drop the mock-llm webServer from playwright.config.mock.ts and set LIBRECHAT_TEST_RUN_HOOK

* 🧹 test: Retire Standalone Mock LLM Server From E2E Recorder

Migrate the `--profile=mock` recorder onto the same in-process fake model
as the Playwright mock suite, then delete the now-unused HTTP mock server
so the fake-LLM logic lives in a single place.

- Point record.js mock profile at the fake model via LIBRECHAT_TEST_RUN_HOOK
- Remove the mock-llm-server spawn/wait and MOCK_LLM_PORT plumbing from record.js
- Delete e2e/setup/mock-llm-server.js (e2e/setup/fake-model.js is now the only source)
- Update e2e/README.md to describe the in-process fake LLM

* 🏷️ ci: Rename Playwright Mock E2E Check to Playwright E2E Tests

.github/workflows/playwright-mock.yml

@@ -1,4 +1,4 @@
-name: Playwright E2E (Mock LLM)
+name: Playwright E2E Tests
 
 on:
   pull_request:
@@ -22,7 +22,6 @@ env:
 
 jobs:
   e2e:
-    name: Tier-1 smoke (headless Chrome)
     runs-on: ubuntu-latest
     timeout-minutes: 30
     env: