feat: 5-task pilot cross-validation — agent oracle vs SG oracle

Pilot results (hybrid backend, Sonnet 4.6):
- ccx-dep-trace-116: F1=1.000 (3/3 files, k8s TypeMeta chain)
- ccx-dep-trace-176: F1=0.160 (4/12 matched, Envoy over-retrieved 38)
- ccx-domain-071:    F1=0.875 (7/9 matched, Kafka acks chain)
- ccx-migration-022: F1=0.933 (7/7+1 extra, Kafka deprecated API)
- ccx-vuln-remed-011: F1=0.000 (fixture gap — express not in repo set)

Mean F1 (excl fixture-gap): 0.742

Also adds path-suffix fallback to cross_validate_oracles.py
for monorepo staging→published repo path matching.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sjarmak

benchmarks/ccb_mcp_crossrepo_tracing/ccx-dep-trace-116/tests/oracle_answer_agent.json

@@ -0,0 +1,62 @@
+{
+  "files": [
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/api/core/v1/types.go"
+    },
+    {
+      "repo": "kubernetes/api",
+      "path": "core/v1/types.go"
+    },
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go"
+    }
+  ],
+  "symbols": [
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/api/core/v1/types.go",
+      "symbol": "Pod"
+    },
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go",
+      "symbol": "TypeMeta"
+    },
+    {
+      "repo": "kubernetes/api",
+      "path": "core/v1/types.go",
+      "symbol": "Pod"
+    }
+  ],
+  "chain": [
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/api/core/v1/types.go",
+      "symbol": "Pod"
+    },
+    {
+      "repo": "kubernetes/api",
+      "path": "core/v1/types.go",
+      "symbol": "Pod"
+    },
+    {
+      "repo": "kubernetes/kubernetes",
+      "path": "staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go",
+      "symbol": "TypeMeta"
+    }
+  ],
+  "text": "Dependency chain traced across three locations:\n\n1. **kubernetes/kubernetes** \u2014 `staging/src/k8s.io/api/core/v1/types.go`:\n   - Line 21: `metav1 \"k8s.io/apimachinery/pkg/apis/meta/v1\"` \u2014 import alias is `metav1`, path is `k8s.io/apimachinery/pkg/apis/meta/v1`.\n   - Line 5012: `type Pod struct {`\n   - Line 5013: `metav1.TypeMeta \\`json:\",inline\"\\`` \u2014 Pod embeds TypeMeta via the `metav1` alias.\n\n2. **kubernetes/api** (sg-evals__api--v0.32.0) \u2014 `core/v1/types.go`:\n   - This is the published `k8s.io/api` module (a mirror of the staging area).\n   - Line 21: `metav1 \"k8s.io/apimachinery/pkg/apis/meta/v1\"` \u2014 same import alias and path.\n   - Line 5012\u20135013: `type Pod struct { metav1.TypeMeta ... }` \u2014 re-exposes TypeMeta through embedding.\n   - The `kubernetes/api` module does NOT have its own `meta/v1` package; it re-exports TypeMeta by depending on `k8s.io/apimachinery v0.32.0` (see go.mod line 13).\n\n3. **kubernetes/kubernetes** staging for apimachinery \u2014 `staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go`:\n   - Line 42: `type TypeMeta struct {` \u2014 authoritative definition.\n   - Line 49: `Kind string \\`json:\"kind,omitempty\" protobuf:\"bytes,1,opt,name=kind\"\\``\n   - Line 56: `APIVersion string \\`json:\"apiVersion,omitempty\" protobuf:\"bytes,2,opt,name=apiVersion\"\\``\n   - Package comment (line 20) explicitly notes: 'external (serialized) types that lack their own version (e.g TypeMeta)'.",
+  "_metadata": {
+    "generator": "context_retrieval_agent",
+    "model": "claude-sonnet-4-6",
+    "backend": "hybrid",
+    "input_tokens": 151568,
+    "output_tokens": 5341,
+    "tool_calls": 35,
+    "elapsed_sec": 68.2,
+    "cost_usd": 0.5348,
+    "timestamp": "2026-03-01T23:34:20.785209+00:00"
+  }
+}