feat: add CUDA (.cu/.cuh) and IEC 61131-3 SCL (.scl/.st) language support

[zouyuanqing]

Summary

Adds language support for CUDA (.cu\ / .cuh) and IEC 61131-3 SCL (.scl\ / .st).

CUDA — Closes #387

Type & extraction

• New \cuda\ language type, mapped to \ ree-sitter-cpp.wasm\ + \cppExtractor\
• .cu\ / .cuh\ extensions
• CUDA is a C++ dialect. The C++ parser handles function definitions, structs, templates, and #include\ directives. Only <<<...>>>\ kernel launch syntax and _global_\ / _device_\ storage specifiers may parse as errors — the test comment explicitly documents this limitation.

Resolution pipeline (the part that makes this actually useful)

CUDA files now share the full C/C++ resolution path:

Module	Change
\import-resolver.ts\	.cuh\ / .cu\ in extension resolution; -I\ include-dir search; standard library detection; import mappings (all gated with |
\
ame-matcher.ts\	CUDA added to C family (\c: 'c', cpp: 'c', cuda: 'c') for cross-language resolution
\index.ts\	Namespace filtering shared with C/C++

This means #include\ references from .cu\ files resolve to their headers, cross-file function calls produce edges, and .cu\ ↔ .cpp\ ↔ .h\ cross-references work correctly.

SCL (IEC 61131-3 ST) — Advances #441

• New \scl\ language type, .scl\ / .st\ extensions
• File-level tracking only (matching yaml/twig/properties conventions)
• \GrammarLanguage\ type explicitly excludes \scl\ to prevent type errors
• Fix: SCL files were silently dropped during single-file indexing — \isLanguageSupported\ now returns \ rue\

Tests (149 new lines)

SCL

• Language detection by extension
• Support / grammar-loaded / file-level-only flags
• End-to-end file-record tracking: 2 ST files indexed, verified both appear in \getFiles()\ with correct \language: scl, zero symbol nodes

CUDA

• Fixture extraction from realistic selective-scan kernel (\selective_scan.cu)
• _global_\ and _host_\ functions extracted with \language: cuda\
• #include <cuda_runtime.h>\ as import node
• Function call edges within CUDA code
• .cuh\ header struct definition extraction

Files changed

File	+	-	Notes
\src/types.ts\	2	0	LANGUAGES
\src/extraction/grammars.ts\	7	2	EXTENSION_MAP, WASM, display, type fix
\src/extraction/languages/index.ts\	1	0	cuda → cppExtractor
\src/resolution/import-resolver.ts\	7	4	Full C++ resolution sharing
\src/resolution/index.ts\	1	1	Namespace filtering
\src/resolution/name-matcher.ts\	1	1	C family membership
_tests_/extraction.test.ts\	149	1	SCL + CUDA test suites
_tests_/fixtures/cuda/selective_scan.cu\	32	0	Real kernel fixture
\CHANGELOG.md\	7	0	Unreleased entries

Total: +216 −10

Not in this PR

• \ ree-sitter-cuda.wasm\ (separate grammar — can replace C++ wasm in follow-up)
• SCL extractor (foundation only — \ ree-sitter-structured-text\ grammar exists and can be vendored in a follow-up)
• PTX (.ptx) — no tree-sitter grammar; requires new grammar from scratch