ci: build + run Qt-side tests on Linux and Windows (Qt6); fix TSan regex

The parent CI workflows (ci-linux.yml, ci-macos.yml, ci-win.yml)
previously produced release artifacts only and did not exercise
the test suite -- the Qt-side tests (test_syncservice,
test_sync_classifier, test_sync_ops, test_syncops_gate_release,
test_syncservice_lifecycle, test_syncservice_credentials_cleanup,
etc.) had zero CI coverage.

Add ctest invocation after the packaging build on:
- ci-linux.yml: full ctest with QT_QPA_PLATFORM=offscreen and
  LD_LIBRARY_PATH pointing at the in-build libVTextEdit.so so
  Qt-side test exes resolve the shared lib at load time.
- ci-win.yml: ctest gated on matrix.config.qt_major == 6 (the
  Qt5 entry must remain packaging-only because
  tests/CMakeLists.txt hard-requires find_package(Qt6 REQUIRED)).
  VNOTE_BUILD_TESTS now toggles based on qt_major instead of being
  unconditionally OFF.

Also fix ci-linux-tsan.yml regex so test_vxcore_sync_is_registered
(introduced in 4fca0d8 in libs/vxcore) is picked up under
ThreadSanitizer. test_vxcore_sync_cancellable_api and
test_sync_credentials_api were also missing from the regex; added
them for completeness.

ci-macos.yml is left untouched here; macOS test enablement
requires similar offscreen setup and is out of scope for this
immediate sync-fix follow-up.

Author: tamlok

.github/workflows/ci-linux-tsan.yml

@@ -105,7 +105,7 @@ jobs:
       - name: Run Sync Test Subset (ThreadSanitizer)
         run: |
           ctest --test-dir libs/vxcore/build_test -C Debug \
-            -R "^test_(sync|git_sync|gitkeep|mock_sync_backend|libgit2_init|sync_backend_metadata|sync_backend_registry|git_backend_autoreg|sync_manager_factory_override|sync_manager_unknown_backend|git_options|credential_provider|sync_backend_with_provider|event_manager|buffer_save|libgit2_init_propagation|sync_config_backcompat|sync_status_queries|sync_config_cache|dirty_tracker|sync_manager_reentrancy|sync_thread_safety)$" \
+            -R "^test_(sync|git_sync|gitkeep|mock_sync_backend|libgit2_init|sync_backend_metadata|sync_backend_registry|git_backend_autoreg|sync_manager_factory_override|sync_manager_unknown_backend|git_options|credential_provider|sync_backend_with_provider|event_manager|buffer_save|libgit2_init_propagation|sync_config_backcompat|sync_status_queries|sync_config_cache|dirty_tracker|sync_manager_reentrancy|sync_thread_safety|vxcore_sync_is_registered|vxcore_sync_cancellable_api|sync_credentials_api)$" \
             --output-on-failure
         env:
           TSAN_OPTIONS: "halt_on_error=1:exitcode=66"

.github/workflows/ci-linux.yml

@@ -121,6 +121,21 @@ jobs:
           cmake --build . --target pack
         working-directory: ${{runner.workspace}}/build
 
+      - name: Build and Run Tests
+        # Build remaining targets (Qt-side tests + vxcore tests; --target pack
+        # above only built the AppImage target) then run them headlessly via
+        # the Qt offscreen platform plugin. VNOTE_BUILD_TESTS defaults to ON
+        # in the root CMakeLists.txt, so no extra -D is needed.
+        run: |
+          set -e
+          cmake --build .
+          export QT_QPA_PLATFORM=offscreen
+          # libVTextEdit.so lives next to the parent build's vnote binary;
+          # add it to LD_LIBRARY_PATH so Qt-side test exes resolve it at load.
+          export LD_LIBRARY_PATH="${{runner.workspace}}/build/libs/vtextedit/src:${LD_LIBRARY_PATH:-}"
+          ctest --output-on-failure
+        working-directory: ${{runner.workspace}}/build
+
       - name: Fix Package
         run: |
           mkdir fixpackage

.github/workflows/ci-win.yml

@@ -123,18 +123,35 @@ jobs:
           QT_MAJOR: ${{ matrix.config.qt_major }}
           VS_CMD: ${{ matrix.config.vs_cmd }}
           RUNNER_WORKSPACE: ${{ runner.workspace }}
+          # tests/CMakeLists.txt hard-requires Qt6 (find_package(Qt6 REQUIRED)),
+          # so the Qt5 matrix entry MUST build packaging-only. Qt6 entry builds
+          # tests so the Build-and-Run-Tests step below can ctest them.
+          VNOTE_TESTS: ${{ matrix.config.qt_major == 6 && 'ON' || 'OFF' }}
         run: |
           cmake --version
           if "%QT_MAJOR%"=="6" call "%VS_CMD%"
           where cl || echo "cl.exe not on PATH"
-          cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=cl -DQT_DEFAULT_MAJOR_VERSION=%QT_MAJOR% -DVNOTE_BUILD_TESTS=OFF -DOPENSSL_EXTRA_LIB_DIR=%RUNNER_WORKSPACE%\build\openssl-utils.git\1.1.1j\Win_x64 %GITHUB_WORKSPACE% > cmake-configure.log 2>&1 || (type cmake-configure.log && exit /b 1)
+          cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=cl -DQT_DEFAULT_MAJOR_VERSION=%QT_MAJOR% -DVNOTE_BUILD_TESTS=%VNOTE_TESTS% -DOPENSSL_EXTRA_LIB_DIR=%RUNNER_WORKSPACE%\build\openssl-utils.git\1.1.1j\Win_x64 %GITHUB_WORKSPACE% > cmake-configure.log 2>&1 || (type cmake-configure.log && exit /b 1)
           type cmake-configure.log
           cmake --build .
           cmake --build . --target=pack
           7z x VNote*.zip -o*
           dir
         working-directory: ${{runner.workspace}}/build
 
+      - name: Build and Run Tests (Qt6 only)
+        # tests/CMakeLists.txt hard-requires Qt6 so this step is skipped on
+        # the Qt5 matrix entry. The previous step already built tests when
+        # VNOTE_BUILD_TESTS=ON, so ctest only needs to dispatch them.
+        if: ${{ matrix.config.qt_major == 6 }}
+        shell: cmd
+        env:
+          VS_CMD: ${{ matrix.config.vs_cmd }}
+        run: |
+          call "%VS_CMD%"
+          ctest -C Release --output-on-failure
+        working-directory: ${{runner.workspace}}/build
+
       - name: Assert MSVC v142 + Qt 5.15.2 in use
         if: ${{ matrix.config.qt_major == 5 }}
         shell: bash