feat: add C++ support with ImGui/ImPlot framework and vendor submodules

Añade soporte C++ al registry: vendor submodules (glfw, imgui, implot, tracy),
sistema de build con CMake y toolchains cross-platform, runner C++ en fn CLI,
parser de tests Google Test, y funciones bash para build Linux/Windows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

registry/test_parser.go

@@ -35,6 +35,8 @@ func parseTestFile(path, lang string) ([]testCase, error) {
 		return parsePythonTests(content), nil
 	case "bash":
 		return parseBashTests(content), nil
+	case "cpp":
+		return parseCppTests(content), nil
 	default:
 		return nil, nil
 	}
@@ -115,6 +117,23 @@ func parseBashTests(content string) []testCase {
 	return extractBlocks(lines, positions)
 }
 
+// parseCppTests extracts C++ test functions (Google Test TEST/TEST_F macros).
+var cppTestRe = regexp.MustCompile(`(?m)^(?:TEST|TEST_F|TEST_P)\s*\(\s*(\w+)\s*,\s*(\w+)\s*\)`)
+
+func parseCppTests(content string) []testCase {
+	lines := strings.Split(content, "\n")
+	var positions []testPos
+
+	for i, line := range lines {
+		if m := cppTestRe.FindStringSubmatch(line); m != nil {
+			name := m[1] + "." + m[2] // Suite.TestName
+			positions = append(positions, testPos{name: name, startLine: i})
+		}
+	}
+
+	return extractBlocks(lines, positions)
+}
+
 // extractBlocks splits lines into code blocks based on test positions.
 func extractBlocks(lines []string, positions []testPos) []testCase {
 	var tests []testCase