feat(extraction): vendor current C/C++ grammars (R7a prep) — c v0.24.2 + cpp v0.23.4, sha-matched (#1345)

tree-sitter-wasms shipped 2023-era C/C++ grammars; the kernel walker must
compile the crates.io versions, so production wasm upgrades FIRST and in
isolation (the R2 pattern). Built with tree-sitter-cli 0.25.10 from each
tag's CHECKED-IN parser.c: tree-sitter-c v0.24.2 (b780e47, parser.c
f2883ff9), tree-sitter-cpp v0.23.4 (f41e1a0, parser.c 2a35a43b, scanner.c
cf60387d) — sha-matched against the crates.io tarballs. .metal/.cu map to
language 'cpp' so the dialects ride the same coherent grammar.

Full suite green with the upgraded grammars (2,490; one unrelated daemon
idle-timeout flake passed solo 9/9) — incl. the UE-macro, misparse-guard,
Metal, and CUDA coverage. Checklist updated with the vendored revs and the
metal/cuda routing correction.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/extraction/grammars.ts

@@ -292,6 +292,11 @@ const VENDORED_WASM_LANGS: ReadonlySet<GrammarLanguage> = new Set([
   'pascal', 'scala', 'lua', 'luau', 'csharp', 'r', 'cfml', 'cfscript', 'cfquery',
   'cobol', 'vbnet', 'erlang', 'terraform', 'arkts', 'nix',
   'typescript', 'tsx', 'javascript', 'jsx', 'java', 'python', 'go',
+  // R7a (C/C++ kernel port prep): tree-sitter-c v0.24.2 (b780e47) +
+  // tree-sitter-cpp v0.23.4 (f41e1a0), parser.c/scanner.c sha-matched against
+  // the crates.io tarballs. `.metal`/`.cu` map to language 'cpp', so the
+  // dialects ride the same (single, coherent) upgraded grammar.
+  'c', 'cpp',
 ]);
 
 /** Absolute path of a language's grammar WASM (vendored or tree-sitter-wasms). */