ci: v2 build + unit + integration workflow, nightly E2E (Task 61)

.github/workflows/v2-ci.yml runs on push/PR to v2-akka-fuse + master:
  - build job: dotnet restore + build (Release)
  - unit-tests job: matrix over the 5 v2 test projects (Cluster, ControlPlane,
    Runtime, Security, OpcUaServer) with Category!=E2E
  - integration job: Host.IntegrationTests with Category!=E2E

.github/workflows/v2-e2e.yml runs nightly at 03:00 UTC + workflow_dispatch:
  - Brings up the docker-dev four-node fleet (admin pair + driver pair + SQL
    + LDAP + Traefik)
  - Waits up to 60s for /health/active to return 200
  - Runs Category=E2E only
  - Always tears down with -v

Both workflows pin .NET 10 via actions/setup-dotnet (no global.json so any
10.0 SDK works). Compatible with both GitHub Actions and Gitea Actions
(act_runner). The E2E filter currently matches zero tests because the
tests/Server/ZB.MOM.WW.OtOpcUa.E2ETests project doesn't exist yet — it lands
when F10/F11/F12 wire enough engine for an end-to-end round-trip to be
meaningful.

.github/workflows/v2-ci.yml

@@ -0,0 +1,70 @@
+# CI for the v2 branch — runs on every push + PR to the v2-akka-fuse / master
+# branches. Layered into three jobs:
+#   build           dotnet restore + build (fast feedback on compile errors)
+#   unit-tests      every v2 unit-test project
+#   integration     2-node Host.IntegrationTests harness
+#
+# Skips E2E (Category=E2E) — that runs nightly via v2-e2e.yml against the full
+# four-node docker-dev stack.
+#
+# Compatible with both GitHub Actions and Gitea Actions (act_runner). The .NET 10
+# SDK is pinned via global.json at the repo root; if no global.json exists, the
+# setup-dotnet step falls back to dotnet-version below.
+
+name: v2-ci
+
+on:
+  push:
+    branches: [v2-akka-fuse, master]
+  pull_request:
+    branches: [v2-akka-fuse, master]
+  workflow_dispatch: {}
+
+env:
+  DOTNET_NOLOGO: "1"
+  DOTNET_CLI_TELEMETRY_OPTOUT: "1"
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+      - name: dotnet restore
+        run: dotnet restore ZB.MOM.WW.OtOpcUa.slnx
+      - name: dotnet build
+        run: dotnet build ZB.MOM.WW.OtOpcUa.slnx --no-restore --configuration Release
+
+  unit-tests:
+    needs: build
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        project:
+          - tests/Core/ZB.MOM.WW.OtOpcUa.Cluster.Tests
+          - tests/Server/ZB.MOM.WW.OtOpcUa.ControlPlane.Tests
+          - tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests
+          - tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests
+          - tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+      - name: dotnet test ${{ matrix.project }}
+        run: dotnet test ${{ matrix.project }} --configuration Release --filter "Category!=E2E"
+
+  integration:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+      - name: dotnet test Host.IntegrationTests
+        run: dotnet test tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests --configuration Release --filter "Category!=E2E"