fix: remediate findings F045, F047, F048, F064, F070, F071, F076-F079

Phase 1 — Trivial fixes:
- F071: Add Uri.EscapeDataString to GetPveTemplateCmdlet node path
- F077: Add ValidateRange(100, 999999999) to GetPveTaskListCmdlet.VmId
- F076: Create .github/dependabot.yml (nuget + github-actions, weekly)
- F079: Fix unit-tests.yml dotnet SDK from 9.0.x to 10.0.x
- F048: Mark wont_fix — sync-over-async accepted for PS 5.1 compat

Phase 2 — Framework targeting (D009 compliance):
- F047: Reduce publishable csproj to netstandard2.0 only, remove all
  #if NET48/NETSTANDARD2_0 conditionals from PveHttpClient.cs,
  restructure build.yml for netstandard2.0 publish + net10.0/net48 tests
- F064: Resolved by F047 — SMA 7.5.0 ItemGroup removed with net10.0 TFM
- F070: Add PS 5.1 smoke-test job to publish.yml (windows-latest)

Phase 3 — IPveHttpClient interface extraction (F045):
- Extract IPveHttpClient interface from PveHttpClient
- Add constructor injection to all 14 service classes
- Services use injected client when available, create+dispose when not

Phase 4 — Service unit tests (F078):
- 196 new xUnit tests across 10 service test files
- All services tested via Moq-mocked IPveHttpClient
- Total test count: 382 (was 186)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/build.yml

@@ -7,53 +7,39 @@ on:
     branches: [ main ]
 
 jobs:
-  build-net48:
-    runs-on: windows-latest
-    timeout-minutes: 15
-    steps:
-      - uses: actions/checkout@v5
-      - name: Setup .NET
-        uses: actions/setup-dotnet@v5
-        with:
-          dotnet-version: '10.0.x'
-      - name: Restore dependencies
-        run: |
-          dotnet restore src/PSProxmoxVE/PSProxmoxVE.csproj
-          dotnet restore tests/PSProxmoxVE.Core.Tests/PSProxmoxVE.Core.Tests.csproj
-      - name: Build net48
-        run: |
-          dotnet build src/PSProxmoxVE/PSProxmoxVE.csproj --configuration Release --framework net48 --no-restore
-          dotnet build tests/PSProxmoxVE.Core.Tests/PSProxmoxVE.Core.Tests.csproj --configuration Release --framework net48 --no-restore
-      - name: Test net48
-        run: dotnet test tests/PSProxmoxVE.Core.Tests/PSProxmoxVE.Core.Tests.csproj --configuration Release --framework net48 --no-build --verbosity normal --collect:"XPlat Code Coverage" --results-directory ./coverage
-      - name: Upload coverage
-        if: always()
-        uses: actions/upload-artifact@v7
-        with:
-          name: coverage-net48
-          path: ./coverage
-
-  build-net10:
+  build-and-test:
     strategy:
+      fail-fast: false
       matrix:
-        os: [windows-latest, ubuntu-latest]
+        include:
+          - os: windows-latest
+            test-framework: net48
+          - os: windows-latest
+            test-framework: net10.0
+          - os: ubuntu-latest
+            test-framework: net10.0
     runs-on: ${{ matrix.os }}
     timeout-minutes: 15
     steps:
       - uses: actions/checkout@v5
+
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
         with:
           dotnet-version: '10.0.x'
+
       - name: Restore dependencies
         run: dotnet restore
-      - name: Build net10.0
-        run: dotnet build --configuration Release --framework net10.0 --no-restore
-      - name: Test net10.0
-        run: dotnet test tests/PSProxmoxVE.Core.Tests/PSProxmoxVE.Core.Tests.csproj --configuration Release --framework net10.0 --no-build --verbosity normal --collect:"XPlat Code Coverage" --results-directory ./coverage
+
+      - name: Build solution
+        run: dotnet build --configuration Release --no-restore
+
+      - name: Run xUnit tests
+        run: dotnet test tests/PSProxmoxVE.Core.Tests/PSProxmoxVE.Core.Tests.csproj --configuration Release --framework ${{ matrix.test-framework }} --no-build --verbosity normal --collect:"XPlat Code Coverage" --results-directory ./coverage
+
       - name: Upload coverage
         if: always()
         uses: actions/upload-artifact@v7
         with:
-          name: coverage-net10-${{ matrix.os }}
+          name: coverage-${{ matrix.test-framework }}-${{ matrix.os }}
           path: ./coverage