perf(executors): lazy-load the executor registry — defer class imports + construction to first use (#11220) (#11421)

Validated in a combined 3-PR batch worktree off release/v3.8.51 tip (a sibling PR from the same author, #11495, was held out — a typecheck error in zai-web.ts only reproduced with this PR + #11495 boarded together, and cleared without #11495; isolated this PR alone confirmed clean on its own too, so the interaction belonged to #11495's side — see its comment).
- Golden lock: executor-map-golden.test.ts — passes byte-identical (same keys, classes, provider identities, dispatch guards)
- Focused tests part of batch's 94/94 node:test run
- typecheck:core, file-size, changelog-integrity, complexity, cognitive-complexity — all OK
- Full-repo lint: 228 pre-existing dashboard react-hooks/* findings, unrelated to this diff

Thanks for the measured, careful methodology here — the golden-lock contract plus the isolated DATA_DIR benchmarking make this an easy PR to trust despite the wide surface (72 files).

src/lib/compression/judgeModelClient.ts

@@ -18,9 +18,10 @@ export function createPricedJudgeClient(
   provider: string,
   credentials: ProviderCredentials
 ): ModelClient {
-  const executor = getExecutor(provider);
   return {
     async complete(model: string, messages: ChatTurn[]): Promise<ModelCallResult> {
+      // #11220: getExecutor is async (lazy registry) — resolve per call.
+      const executor = await getExecutor(provider);
       const input: ExecuteInput = {
         model,
         body: { model, messages, stream: false },