Context

Follow-up from #85264 (scoped Windows path realpath caches).

The scoped-cache PR addresses plugin hook/skill resolution and sandbox host-path validation paths, but the largest remaining lstat gap is in src/plugins/manifest-registry-installed.ts:

• buildInstalledManifestRegistryIndexKey() is called ~179 times per config validation
• Each call creates a new scoped Map(), causing redundant filesystem lookups
• This accounts for most of the ~13s gap between global cache (8.7s startup) and scoped cache (14.0s startup) on Windows

Proposed approaches

1. Lift cache scope — reuse a single Map across the ~179 calls within one config-validation pass
2. Short-lived module-level cache — cache at the module level with a short TTL, cleared after validation completes
3. Accept current improvement — the scoped cache already achieves a 55% lstat reduction vs no cache; further optimization is optional

Performance data

CPU profile artifacts: https://gist.github.com/211-lee/cd460d7292a7797043a877f5a3980d25

Related

• PR: fix(infra): scope Windows path realpath caches #85264