feat(kernel): R7a C/C++ walker — dual-lang ccpp module, preParse hoist, 7 new blanks, c/cpp default-routed (#1346)

Parity: 0 diffs on redis/git/fmt/protobuf/ALS sweeps; full-init dumps
byte-identical on all five + linux at kernel scale (10.4M dump lines,
same sha256 both arms). Linux 2c/6GB envelope: kernel-arm 19.1min vs
wasm-arm 22.9min (parse 356s vs 435s) on a much richer graph (the new
blanks recover error-swallowed code: git 2x nodes, linux kernel/+mm/ 3x).
Deferral guard corrected by measurement (C/C++ error incidence 9-42%;
--max-deferral flag); defer-reuse memo kills the 3x re-blank/re-parse
cost deferred files paid.

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

codegraph-kernel/src/lib.rs

@@ -17,6 +17,7 @@
 #![deny(clippy::all)]
 
 mod buffers;
+mod ccpp;
 mod docstring;
 mod ids;
 mod go;
@@ -103,6 +104,7 @@ pub fn extract_file(file_path: String, content: String, language: String) -> Res
         "java" => java::extract(&file_path, &content).map_err(Error::from_reason)?,
         "python" => python::extract(&file_path, &content).map_err(Error::from_reason)?,
         "go" => go::extract(&file_path, &content).map_err(Error::from_reason)?,
+        "c" | "cpp" => ccpp::extract(&file_path, &content, &language).map_err(Error::from_reason)?,
         _ => tsjs::extract(&file_path, &content, &language).map_err(Error::from_reason)?,
     };
     Ok(ExtractBuffers {