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>

__tests__/kernel-scaffold.test.ts

@@ -72,8 +72,8 @@ describe.skipIf(!kernelBuilt)('kernel scaffold', () => {
     expect(info.languages).toContain('javascript');
   });
 
-  it('TS/JS family routes to the kernel by default (R3 default-on); others stay wasm', () => {
-    for (const lang of ['typescript', 'tsx', 'javascript', 'jsx'] as const) {
+  it('TS/JS family + Java route to the kernel by default; others stay wasm', () => {
+    for (const lang of ['typescript', 'tsx', 'javascript', 'jsx', 'java'] as const) {
       expect(kernelRoutes(lang), lang).toBe(true);
     }
     expect(kernelRoutes('python')).toBe(false);