perf(ci): use tsrs and reduce PE acceptance startup (#5795)

Use pinned tsrs on supported development hosts while retaining stable official
TypeScript on Windows and unsupported platforms. Partition compile/typecheck
caches by actual compiler and qualify fallback hosts for compiler inputs and
lifecycle hooks.

Reduce PE acceptance startup through the existing bounded compiled CLI. Retain
upstream named MCP definitions, every fixture/assertion and the original 30s
deadline. Verify that browser transport loss preserves the observed target.

Validation: full qualification and real host lanes in
https://github.com/morluto/rea/actions/runs/39590450889 ; 450 focused regressions
passed with two documented conditional skips. All 1724 production emit files
match SHA-256 and size across both compilers. Current-head Codex/Greptile review
found no actionable issues. Measurements and limitations are in the PR.

Assisted-by: Reimu (gensokyo-skills:reimu-incident-triage)

.github/workflows/ci.yml

@@ -819,6 +819,11 @@ jobs:
         with:
           save: "true"
       - run: npm ci
+      - name: Typecheck with the official Windows compiler
+        env:
+          GOMAXPROCS: "2"
+          GOMEMLIMIT: "3GiB"
+        run: npm run typecheck -- --checkers 2
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         with:
           name: rea-build-cache
@@ -849,6 +854,7 @@ jobs:
           npx vitest run --coverage.enabled=false
           src/process/capture/FilesystemSnapshot.test.ts
           tests/process-global/filesystemSnapshotFallbackCancellation.test.ts
+          tests/boundary/filesystem/typescriptCompiler.test.ts
           tests/boundary/filesystem/binaryTarget.test.ts
           tests/boundary/filesystem/safeOutputTree.test.ts
           tests/boundary/providers/native/artifactProvider.archiveSafety.test.ts