test(gencpp): add full gencpp/base samples and comprehensive test suite

- Copied 58 files from C:\projects\gencpp\base\ to tests/assets/gencpp_samples
- Added test_gencpp_full_suite.py that validates:
  - Skeleton generation for all .hpp files
  - Code outline generation
  - get_definition for key symbols
  - AST masking with aggregation
- All 25 tests pass

tests/assets/gencpp_samples/gen.dep.cpp

@@ -0,0 +1,18 @@
+// This file is intended to be included within gen.cpp (There is no pragma diagnostic ignores)
+#include "gen.dep.hpp"
+
+#include "dependencies/src_start.cpp"
+
+GEN_NS_BEGIN
+
+#include "dependencies/debug.cpp"
+#include "dependencies/string_ops.cpp"
+#include "dependencies/printing.cpp"
+#include "dependencies/memory.cpp"
+#include "dependencies/hashing.cpp"
+#include "dependencies/strings.cpp"
+#include "dependencies/filesystem.cpp"
+#include "dependencies/timing.cpp"
+#include "dependencies/parsing.cpp"
+
+GEN_NS_END