feat(kernel): R4 — Java port with Lombok synthesis, gate passed, default-on

Java joins the native kernel (codegraph-kernel/src/java.rs), mirroring
the wasm extractor's Java paths bug-for-bug: package namespaces,
imports, javadoc, annotations→decorates, type_list inheritance,
static-final constants, enum constants, anonymous classes (including
the TS side's 0-based-line quirk on the extends ref), method_invocation
calls with the this.field unwrap and the Foo.getInstance().bar() chain
encoding (#645/#608), static-member value reads, method-reference
fn-refs (#756), value-reference edges, and the full Lombok member
synthesizer (#912: Getter/Setter/Data/Value/Builder/ToString/
EqualsAndHashCode/Slf4j-family with taken-member dedup). The shared
docstring/textutil modules moved to crate level. Grammar:
tree-sitter-java 0.23.5, with the wasm grammar vendored from the same
tag (parser.c sha-matched) replacing tree-sitter-wasms' 2023-era build.

Gate (plan §4c): extraction sweeps 100% — gson 262/262, retrofit
341/341, dubbo 4,048/4,048 — plus a Java torture fixture in npm test;
full-init dump-diffs byte-identical on gson (49,766 rows), retrofit
(62,735), and dubbo (441,266 rows); all R2/R3 repos re-verified; Linux
container runs all 23 kernel tests green under CODEGRAPH_KERNEL_EXPECT=1.

The gate caught a real cross-language bug: fn-ref dedupe and value-ref
self-target checks must compare node ID STRINGS, not node-table rows —
ids collide for same-(kind, name, line) nodes, which minified one-line
bundles hit routinely (retrofit's website JS exposed it; latent in the
TS/JS walker since R2, never released). Fixed in both walkers.

Benchmark honesty: dubbo fresh-init on an 11-core Mac is ~flat
(parse-loop wall 5,020→4,394ms; total ~11.3s both arms) because that
wall is main-thread-bound (reads + store), not worker-CPU-bound — the
§6 expectation assumed otherwise. Where worker CPU binds the kernel
delivers: dubbo on a 2-CPU/6GB container drops 27.8-28.6s → 22.3-22.8s
(~1.25×). The identified lever for the many-core headline is decoding
kernel buffers directly into store rows (skipping per-node JS object
materialization); the buffer contract already carries everything.

DEFAULT_ROUTED now includes java. Full suite: 2,467 tests pass.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

codegraph-kernel/src/lib.rs

@@ -17,8 +17,11 @@
 #![deny(clippy::all)]
 
 mod buffers;
+mod docstring;
 mod ids;
+mod java;
 mod langs;
+mod textutil;
 mod tsjs;
 
 use napi::bindgen_prelude::*;
@@ -94,7 +97,10 @@ pub fn grammar_info(language: String) -> Option<GrammarInfo> {
 
 #[napi]
 pub fn extract_file(file_path: String, content: String, language: String) -> Result<ExtractBuffers> {
-    let out = tsjs::extract(&file_path, &content, &language).map_err(Error::from_reason)?;
+    let out = match language.as_str() {
+        "java" => java::extract(&file_path, &content).map_err(Error::from_reason)?,
+        _ => tsjs::extract(&file_path, &content, &language).map_err(Error::from_reason)?,
+    };
     Ok(ExtractBuffers {
         meta: out.meta.into(),
         nodes: out.nodes.into(),