chore: add CodeRabbit Playwright path instruction

Route changed browser_tests/**/*.spec.ts and apps/website/e2e/**/*.spec.ts files through CodeRabbit guidance that explicitly names .agents/checks/test-quality.md and docs/testing/README.md as required review context.

Verification: parsed .coderabbit.yaml with Ruby YAML and ran git diff --check.

Author: huang47

.coderabbit.yaml

@@ -93,3 +93,11 @@ reviews:
         When a PR changes litegraph graph deserialization, link loading, nullable serialized links, or sparse legacy link handling, require direct regression coverage for the changed runtime path. Helper-only coverage in a different utility is insufficient.
         For `LGraph.configure()` sparse legacy links, expect a test that constructs an `LGraph`, calls `configure()` with a v0.4 payload containing `links: [null, validLink]`, asserts it does not throw, and asserts the valid link is still created.
         For link-retargeting or widget-slot compression changes such as `compressWidgetInputSlots()`, expect a direct test of the compression path with `links: [null, validLink]` that proves the valid link is still retargeted while the null entry is ignored.
+    - path: '{browser_tests,apps/website/e2e}/**/*.spec.ts'
+      instructions: |
+        Treat `.agents/checks/test-quality.md` and `docs/testing/README.md` as required review context for every changed Playwright test file.
+        Flag missing behavioral coverage, change-detector tests, mock-heavy tests, snapshot abuse, fragile assertions, missing edge cases, unclear setup, and test isolation problems.
+        Every route.fulfill() body must be typed with generated types or schemas from packages/ingest-types, packages/registry-types, src/workbench/extensions/manager/types/generatedManagerTypes.ts, or src/schemas/; flag untyped inline JSON objects.
+        Never use waitForTimeout; use Locator actions and auto-retrying assertions instead.
+        Restrict page.evaluate() to reading internal state or fixture setup; flag any page.evaluate() that drives UI actions when a Playwright action method exists.
+        New shared test helpers must be Playwright fixtures via base.extend(), not properties added to ComfyPage.