perf(synthesis): provably-empty pass gates + prefilters — render/expo/rn/mybatis stop scanning repos they can't match; iface memo (#1389)

Store-arc round 2 (#1388 follow-up). The synthesis pool barrier on dubbo
carried ~1.4s of passes that provably could not emit an edge for the
project: reactRenderEdges fanned out over every class before checking for
a render method (now: one indexed name lookup bounds candidates — not a
language gate, Java Litho-style render+setState still matches);
expo/rn cross-platform pairing streamed every method row without the
languages their edges require (now registry-gated: expo needs swift AND
kotlin file-languages, rn needs a JS-family caller for isBridge);
mybatis built its full java-method index before discovering there were no
mapper-XML methods (now collects the XML side first). ifaceEdges — real
work — stops re-fetching a hub interface's methods once per implementer
and skips supertype-less classes before any per-class lookup.

dubbo warm wall 8.49-8.79 → 8.14-8.24s (n=3/arm, caffeinated); barrier
784→435ms; the full removed pass work lands on low-core envelopes where
synthesis runs sequentially. Dumps byte-identical: dubbo old-vs-new,
pooled-vs-sequential, kernel-vs-wasm (441,270 rows) + excalidraw JSX-live
control (89,903 rows, 46 react-render edges reproduced). Suite 2,689 ×2
with CODEGRAPH_KERNEL_EXPECT=1.

Also ships the diagnostics that located the round (zero cost when off):
CODEGRAPH_RESOLVE_PROFILE=2 attributes per-ref time to resolveOne's
strategies (stage:*) and the name-matcher's sub-matchers (nm:*);
CODEGRAPH_SYNTH_TIMINGS now prints the store worker's decode-vs-SQL
split. Killed by measurement, recorded in the PR: import-failure negative
cache (both-outcome names exist — static imports resolve via
instance-method on jvm-miss), jvm-miss early return (1,939 later-strategy
edges), jsxEdges language gate (Java generics text produces jsx edges),
and §4d buffer→bind on Spring repos (extract() hook forces the decoded
path — kernel=0 bundles measured).

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

CHANGELOG.md

@@ -24,6 +24,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - Indexing very large projects on multi-core machines got faster again: the parallel-resolution workers now periodically refresh their read-only database connections, which lets database housekeeping advance instead of silently building up a backlog behind long-lived readers — a backlog that was taxing the indexer's own writes. Graphs remain byte-for-byte identical; the win is largest at Linux-kernel scale on many-core machines.
 - Indexing on macOS now uses the machine's real memory headroom when sizing its parallel-resolution workers. macOS deliberately keeps RAM filled with reclaimable cache, so the previous free-memory reading came back tiny (~1GB on an otherwise idle machine) and silently halved the worker pool — a medium Java project's fresh index ran about 15–20% slower than the hardware allowed. Graphs remain byte-for-byte identical; the same fix also lets a memory-driven analysis cache engage fully on macOS for large C codebases.
 - Fresh indexing got a sizeable across-the-board speedup: during the initial build, the database's secondary lookup indexes are set aside and rebuilt once after parsing instead of being maintained row by row — the same proven trick the later linking phase already used, now applied to the whole parse lane — and the reference-resolution loop likewise stops maintaining lookup indexes it never reads, rebuilding them at the end when almost nothing is left in the table. A medium Java project's parse phase runs about 58% faster and its full fresh index about 19% faster end-to-end; a Linux-kernel-scale index that took ~15 minutes on an 8-core machine now completes in about 11, with the resolution phase alone dropping by a third. Graphs remain byte-for-byte identical, and incremental syncs are unaffected.
+- The dynamic-dispatch analysis at the end of indexing now skips passes that provably can't produce anything for the project at hand: React re-render bridging when no class has a `render` method, React Native and Expo cross-platform pairing when the required languages aren't present, and MyBatis mapper linking when there's no mapper XML. Previously each of these scanned the whole graph before coming up empty — on a 4,000-file Java project that was about 0.9 seconds of wasted analysis per fresh index. The interface-implementation bridging pass also got cheaper on real work: it no longer re-fetches a hub interface's method list once per implementer, and classes that extend or implement nothing are skipped before any per-class lookups. Graphs remain byte-for-byte identical.
 - Indexing large C and C++ codebases spends much less time in the function-pointer dispatch analysis (the pass that connects handler tables like a command table or an ops struct to their call sites): each source file is now read and prepared once instead of four times, files that can't contribute any dispatch wiring are skipped outright in the later linking steps, and on platforms with the native engine the per-file scanning itself now runs natively too. On a Linux-kernel-scale tree the pass runs about a third faster end-to-end, with graphs byte-for-byte identical; platforms without a native binary keep the same results on the previous path.
 
 ### Fixes