fix(extraction): detect export-macro-annotated class in .h language check (#1159) (#1207)

Carries #1133 forward onto current main (rebased for conflicts). A lean Unreal-Engine-style `.h` whose only C++ signal is `class ENGINE_API Foo : public Bar` (no public:/virtual/namespace/template) was misdetected as C and its class + inheritance edge silently dropped; looksLikeCpp now recognizes the export-macro-annotated class/struct shape, matching what blankCppExportMacros already recovers.

Fixes #1159.

Co-Authored-By: robertyluo <robertyluo@tencent.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>