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/dependencies/timing.hpp

@@ -0,0 +1,19 @@
+#ifdef INTELLISENSE_DIRECTIVES
+#	pragma once
+#	include "filesystem.hpp"
+#endif
+
+#pragma region Timing
+
+#ifdef GEN_BENCHMARK
+//! Return CPU timestamp.
+GEN_API u64 read_cpu_time_stamp_counter( void );
+
+//! Return relative time (in seconds) since the application start.
+GEN_API f64 time_rel( void );
+
+//! Return relative time since the application start.
+GEN_API u64 time_rel_ms( void );
+#endif
+
+#pragma endregion Timing