fix: replace C++20 designated initializers with C++17-compatible syntax in tests

The CI build failed because constraint_parser_test.cpp used designated
initializers ({.case_sensitive = true}), which require C++20 or later.
Also fix lcov mismatch error in CI coverage report generation.

Author: libraz

.github/workflows/ci.yml

@@ -83,7 +83,7 @@ jobs:
       - name: Generate coverage report
         run: |
           mkdir -p build/coverage
-          lcov --directory build --capture --output-file build/coverage/coverage.info --ignore-errors source,gcov
+          lcov --directory build --capture --output-file build/coverage/coverage.info --ignore-errors source,gcov,mismatch
           lcov --extract build/coverage/coverage.info "${PWD}/src/*" --output-file build/coverage/coverage_filtered.info --ignore-errors unused
 
       - name: Upload coverage to Codecov

tests/model/constraint_parser_test.cpp

@@ -443,7 +443,8 @@ TEST(ConstraintParserTest, CaseInsensitiveDefault) {
 
 TEST(ConstraintParserTest, CaseSensitiveFails) {
   std::vector<Parameter> params = {{"os", {"win", "mac"}, {}}};
-  coverwise::model::ParseOptions opts{.case_sensitive = true};
+  coverwise::model::ParseOptions opts;
+  opts.case_sensitive = true;
 
   // "OS" does not match "os" in case-sensitive mode.
   auto result = ParseConstraint("OS=Win", params, opts);
@@ -452,7 +453,8 @@ TEST(ConstraintParserTest, CaseSensitiveFails) {
 
 TEST(ConstraintParserTest, CaseSensitiveExactMatch) {
   std::vector<Parameter> params = {{"os", {"win", "mac"}, {}}};
-  coverwise::model::ParseOptions opts{.case_sensitive = true};
+  coverwise::model::ParseOptions opts;
+  opts.case_sensitive = true;
 
   // Exact case matches succeed.
   auto result = ParseConstraint("os=win", params, opts);