feat(harness): P5 — customization manifest (rcust)

One block at run start answering "what does this recipe customize?" across every surface
(non-default recipe_meta keys, ops.py pre-ops, install_steps.sh, compose.ccci.yml, lifecycle
overlays by source, custom-test counts, active CCCI_SKIP_GENERIC* env overrides — !!-flagged when
riding a CI run, P2c), printed to the run log and embedded verbatim in results.json under
"customization". Pure presentation — building/printing it never influences a verdict; the
manifest honors the HC2 repo-local gate so it never advertises code the run will not execute.

Unit tests: synthetic recipe exercising every surface -> complete + deterministic + JSON-clean;
HC2 invisibility; env-override flagging; render golden lines; build_results threads the dict
verbatim (key always present, None when absent).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

runner/harness/results.py

@@ -203,6 +203,7 @@ def build_results(
     screenshot: str | None = None,
     summary_card: str | None = None,
     expected_na: dict | None = None,
+    customization: dict | None = None,
 ) -> dict:
     """Assemble the full results.json dict (no I/O). `finished_ts` is passed in (the orchestrator
     stamps it) so this stays pure and deterministic for unit tests. `expected_na` is the recipe's
@@ -236,6 +237,9 @@ def build_results(
         },
         "screenshot": screenshot,
         "summary_card": summary_card,
+        # rcust P5: the run's resolved customization manifest (pure presentation — consumers must
+        # never derive a verdict from it).
+        "customization": customization,
     }