feat(selector): 增加离线候选遍历与严格回放验证 Demo

- 新增 selector_candidate_demo，移除 provenance intent 后枚举候选 selector
- 对候选分支执行有界重建与严格 STEP 比较
- 仅在候选遍历完整且唯一 strict 通过时生成 selector 映射记录
- 增加 selector 候选搜索、预算限制和记录生成的测试
- 保持生产 selector resolver 不受 Demo 逻辑影响
- 更新 CADFS 能力台账，记录 IMPRINT 派生 profile 的 lineage selector 缺口

backend/app/cad_agent/application/workflow.py

@@ -172,7 +172,16 @@ class WorkflowCoordinator:
             for atomic_id in self.runtime.supported_atomic_ids()
         }
         repair_instruction = "" if state.repair_count == 0 else "Return a complete replacement document. Preserve only features confirmed in executed_feature_ids unless the diagnostic identifies that feature. Features that did not execute may be corrected. Keep local names unless the diagnostic identifies a name conflict. Never add IDs, stable selectors, snapshots, or tokens."
-        content = json.dumps({"requirements": requirements, "supported_operations": operation_schemas, "previous_authoring": previous, "diagnostics": diagnostics}, ensure_ascii=False)
+        content = json.dumps({
+            "requirements": self._authoring_requirements_context(requirements),
+            "supported_operations": operation_schemas,
+            "authoring_selector_contract": {
+                "face_cap_source_pattern": r"^[a-z][a-z0-9_]{0,63}\.(top_planar_face|bottom_planar_face|end_face|start_face)$",
+                "face_cap_roles": ["top_planar_face", "bottom_planar_face", "end_face", "start_face"],
+            },
+            "previous_authoring": previous,
+            "diagnostics": diagnostics,
+        }, ensure_ascii=False)
         try:
             raw = await self._tool_call(
                 task_id, author, "write_authoring_cdsl", AuthoringDocument.model_json_schema(),
@@ -343,6 +352,20 @@ class WorkflowCoordinator:
             },
         }
 
+    @staticmethod
+    def _authoring_requirements_context(requirements: dict[str, Any]) -> dict[str, list[str]]:
+        """Pass requirement meaning to the author without leaking analysis field names.
+
+        ``acceptance_targets.expected`` is intentionally an open-ended
+        reporting record. It may contain descriptive keys from a user request,
+        while Authoring CDSL has a closed protocol. Passing it through verbatim
+        invites a model to treat analysis labels as output fields.
+        """
+        return {
+            key: [item for item in requirements.get(key, []) if isinstance(item, str)]
+            for key in ("explicit_requirements", "assumptions", "manual_targets")
+        }
+
     @staticmethod
     def _validate_repair_document(
         previous: dict[str, Any], replacement: dict[str, Any], diagnostics: dict[str, Any] | None,