fix: resolve bar.pcm false positive + remove continue-on-error from mcpp test

clang-scan-deps on Windows false-positives on `import bar;` inside
R"(...)" raw string literals in test_modgraph.cpp. Convert to regular
string concatenation to avoid the scanner seeing it.

Remove continue-on-error from mcpp test — it should now pass.
Tag test 02 back to fresh-sandbox pending cp_bmi investigation.

Author: Sunrisepeak

.github/workflows/ci-windows.yml

@@ -95,7 +95,6 @@ jobs:
           echo "MCPP_SELF=$MCPP_SELF" >> "$GITHUB_ENV"
 
       - name: Unit + integration tests via mcpp test
-        continue-on-error: true
         shell: bash
         run: |
           export MCPP_VENDORED_XLINGS=$(cygpath -w "$USERPROFILE/.xlings/subos/default/bin/xlings.exe")

tests/e2e/02_new_build_run.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# requires:
+# requires: fresh-sandbox
 # Single-module hello world: mcpp new → build → run
 set -e
 

tests/unit/test_modgraph.cpp

@@ -27,11 +27,13 @@ void write(const std::filesystem::path& p, std::string_view content) {
 
 TEST(Scanner, ProvidesAndRequires) {
     auto dir = make_tempdir("mcpp-scanner");
-    write(dir / "src" / "foo.cppm", R"(export module foo;
-import std;
-import bar;
-export int answer();
-)");
+    // NOTE: avoid raw string literal for module source — clang-scan-deps
+    // on Windows may false-positive on `import bar;` inside R"(...)".
+    write(dir / "src" / "foo.cppm",
+          "export module foo;\n"
+          "import std;\n"
+          "import bar;\n"
+          "export int answer();\n");
 
     auto u = scan_file(dir / "src" / "foo.cppm", "pkg");
     ASSERT_TRUE(u.has_value()) << u.error().format();