fix: name matching for default-ns deps + forbidden module name in test

- Name check in SemVer merge path now also accepts the map key name
  (handles synthesize_from_xpkg_lua setting composite package.name)
- Rename test module from 'util' to 'acme.util' (util is a forbidden
  top-level name since 0.0.10)

Author: Sunrisepeak

src/cli.cppm

@@ -1667,14 +1667,15 @@ prepare_build(bool print_fingerprint,
                 {
                     const std::string& expectedShort =
                         spec.shortName.empty() ? name : spec.shortName;
-                    std::string expectedComposite;
-                    if (!spec.namespace_.empty()
-                        && spec.namespace_ != mcpp::manifest::kDefaultNamespace) {
-                        expectedComposite = std::format("{}.{}",
-                            spec.namespace_, expectedShort);
-                    }
+                    // Also accept the fully-qualified form (ns.short) since
+                    // synthesize_from_xpkg_lua may set package.name to the
+                    // composite name for backward compat.
+                    auto expectedComposite = spec.namespace_.empty()
+                        ? std::string{}
+                        : std::format("{}.{}", spec.namespace_, expectedShort);
                     const bool nameOk =
                         newManifest.package.name == expectedShort
+                        || newManifest.package.name == name
                         || (!expectedComposite.empty()
                             && newManifest.package.name == expectedComposite);
                     if (!nameOk) {

tests/e2e/27_namespace_dependencies.sh

@@ -17,7 +17,7 @@ cd "$TMP/util-pkg"
 cd util
 rm -f src/main.cpp
 cat > src/util.cppm <<'EOF'
-export module util;
+export module acme.util;
 import std;
 export int answer() { return 42; }
 EOF
@@ -38,7 +38,7 @@ cd "$TMP/app"
 cd app
 cat > src/main.cpp <<'EOF'
 import std;
-import util;
+import acme.util;
 int main() { std::println("answer = {}", answer()); return answer() == 42 ? 0 : 1; }
 EOF
 cat > mcpp.toml <<EOF