feat(dotnet): add cicd chain contract harness

docs/WBS_10_DOTNET_CICD_CHAIN_CONTRACT.yaml

@@ -0,0 +1,48 @@
+formula_id: WBS_10_DOTNET_CICD_CHAIN_CONTRACT_V1
+owner: QuantEngine
+status: draft
+goal: "CI, prepare-release, deploy-prod 순차 게이트를 고정한다."
+
+workflows:
+  ci:
+    file: .gitea/workflows/ci.yml
+    name: "Validators (Pushes and Pull Requests)"
+    triggers:
+      - push: main
+      - pull_request: main
+    role: "upstream validator"
+  prepare_release:
+    file: .gitea/workflows/prepare-release.yml
+    name: "Prepare Release"
+    triggers:
+      - workflow_run: Validators (Pushes and Pull Requests)
+      - workflow_dispatch
+    role: "release builder"
+    upstream_gate: "Validators (Pushes and Pull Requests) success"
+  deploy_prod:
+    file: .gitea/workflows/deploy-prod.yml
+    name: "Deploy to Production"
+    triggers:
+      - workflow_run: Prepare Release
+      - workflow_dispatch
+    role: "production deployer"
+    upstream_gate: "Prepare Release success"
+
+dependency_chain:
+  - "Validators (Pushes and Pull Requests) -> Prepare Release -> Deploy to Production"
+
+required_guards:
+  - "prepare-release는 Validators 성공 없이는 실행 금지"
+  - "deploy-prod는 Prepare Release 성공 없이는 실행 금지"
+  - "deploy-prod는 upstream CI SHA를 release tag와 대조"
+  - "모든 단계는 concurrency group을 사용해 동일 SHA 중복 실행을 차단"
+
+health_checks:
+  - "upstream workflow conclusion == success"
+  - "release tag sha matches workflow_run head_sha"
+  - "artifact 존재 확인"
+  - "SSH/Gitea secret 존재 확인"
+
+notes:
+  - "순차 게이트는 workflow_run 연결과 검증 스텝 둘 다 필요하다."
+  - "병렬 실행은 금지된다."