Export portable Live evidence bundles

AI-assisted implementation under maintainer direction.

tests/framework-fixtures/README.md

@@ -120,3 +120,38 @@ When `preActions` is omitted, steer smoke inherits `runtime.preActions` to revea
 | `nuxt-csp/` | Nuxt `routeRules` with literal CSP header in `nuxt.config.ts`. CSP shape `append-string`. |
 
 Add new fixtures by cloning a directory, swapping files, and updating `fixture.json`.
+
+## External quality-eval fixtures
+
+The public Live benchmark can execute a fixture owned by another repository
+without copying its task corpus or rubric into Impeccable:
+
+```sh
+bun run bench:live -- \
+  --fixture-dir=/absolute/path/to/private-fixture \
+  --agent=codex \
+  --action=bolder \
+  --iterations=1 \
+  --evidence-bundle=/absolute/path/to/output-bundle
+```
+
+An external fixture has the same shape as a directory in this folder:
+`fixture.json`, `gitignore.txt`, and `files/`. Use the optional
+`evidenceCapture` block in `fixture.json` for rubric-free capture metadata:
+
+```json
+{
+  "evidenceCapture": {
+    "captureSelector": "section.case-study",
+    "viewport": { "width": 1440, "height": 1080 },
+    "action": "bolder"
+  }
+}
+```
+
+The bundle contains `report.json`, the original capture, each progressively
+delivered variant capture, geometry/overflow facts, hashes, and timing data.
+It deliberately cannot run `--judge-rendered`; comparative rubrics, private
+fixtures, human calibration, and quality decisions belong in the consuming
+evaluation harness. The normal public E2E suite remains responsible for Live
+protocol, framework, source-commit, cleanup, and recovery correctness.