Restore explicit gcov generation step in coverage workflow

.github/workflows/test.yml

@@ -3,6 +3,7 @@ name: Test
 on:
   workflow_dispatch:
   pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
   push:
     branches: [ "main" ]
 
@@ -41,6 +42,9 @@ jobs:
             compiler: clang++-17
           - os: ubuntu-24.04
             compiler: clang++-18
+          - os: ubuntu-24.04
+            compiler: clang++-19
+            install: clang-19
           # GCC on macOS
           - os: macos-15
             compiler: g++-13
@@ -89,15 +93,18 @@ jobs:
                                     # but do run twice as many compilation tests as the number of
                                     # available threads
 
-    - name: Codecov
+    - name: Generate coverage reports
       if: contains(matrix.extra_build_flags, 'coverage')
       working-directory: ${{github.workspace}}/build
       run: |
-        echo "Producing coverage reports..."
-        find . -name catch_tests.cpp.gcno -exec gcov -pb {} +
-
-        echo "Finding relevant report..."
-        cov_report=$(find . -name "*scope_guard.hpp.gcov" -exec readlink -e {} +)
-
-        echo "The report is ${cov_report}. Uploading to codecov..."
-        bash <(curl -s https://codecov.io/bash) -f $cov_report
+        # Process test files from project root, excluding dependencies
+        find . -maxdepth 2 -name "*tests.cpp.gcno" -exec gcov -pb {} +
+
+    - name: Codecov
+      if: contains(matrix.extra_build_flags, 'coverage')
+      uses: codecov/codecov-action@v5
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
+        directory: ${{github.workspace}}/build
+        files: . /**/*scope_guard.hpp.gcov
+        flags: unittests