Collect and report coverage for UnitsNet.Modular

The Modular test projects are absent from Build/test-projects.psm1, and this
workflow ran plain dotnet test, so nothing in the repository measured Modular
coverage. codecov.yml targets the 80-100 range, but that target only ever saw
the legacy projects.

Wraps the existing test run in the dotCover tool the repository already
depends on, and uploads the report the same way pr.yml does.

The filter is narrower than the legacy '+:module=UnitsNet*;-:module=*Tests'.
The compatibility suite compiles the current UnitsNet project and generates a
large fixture assembly, so the broad filter reports legacy UnitsNet at 24% and
a 19k-statement generated test fixture at 37%, dragging the headline to 31%
and measuring things this workflow does not own. Restricting it to the two
product assemblies reports what Modular is actually responsible for.

id-token is granted because this workflow, unlike pr.yml, declares its
permissions explicitly, so Codecov's use_oidc would otherwise have no token.

Author: darkfader

.github/workflows/unitsnet-modular-ci.yml

@@ -49,6 +49,9 @@ on:
 
 permissions:
   contents: read
+  # Codecov uploads with use_oidc, which needs a token. This workflow declares its
+  # permissions explicitly, so id-token stays none unless it is named here.
+  id-token: write
 
 concurrency:
   group: unitsnet-modular-ci-${{ github.ref }}
@@ -80,11 +83,29 @@ jobs:
       - name: Restore
         run: dotnet restore UnitsNet.Modular.slnx -p:Platform=ProjectReferences
 
+      - name: Restore local tools
+        run: dotnet tool restore
+
       - name: Build
         run: dotnet build UnitsNet.Modular.slnx --configuration Release --no-restore --no-incremental -p:Platform=ProjectReferences
 
-      - name: Test
-        run: dotnet test UnitsNet.Modular.slnx --configuration Release --no-build -p:Platform=ProjectReferences
+      - name: Test with coverage
+        run: |
+          mkdir -p Artifacts/Coverage
+          dotnet tool run dotCover -- cover-dotnet \
+            --Output "Artifacts/Coverage/UnitsNet.Modular.coverage.xml" \
+            --ReportType DetailedXML \
+            --Filters '+:module=UnitsNet.Modular;+:module=UnitsNet.Modular.Generator;-:module=*Tests;-:module=*Fixture' \
+            --ReturnTargetExitCode \
+            -- test UnitsNet.Modular.slnx --configuration Release --no-build -p:Platform=ProjectReferences
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v6
+        with:
+          directory: Artifacts/Coverage
+          fail_ci_if_error: false
+          plugins: noop
+          use_oidc: true
 
       - name: Native AOT smoke test
         run: |