2026.9.7 lengthened the compile-cache marker from <mtime>-<size> to build-<buildId>, which pushed cache paths on Windows into the directory-length window where Node 24's module.enableCompileCache() never returns (nodejs/node#66438); every OpenClaw process start could then spin at full CPU. The shared cache owner now uses a 16-character hash of the full build id as the marker, refuses Windows cache paths over 200 characters with a recorded warning (cache off for that process), and no longer propagates an unsafe inherited cache path to children. Legacy namespace handling and POSIX behavior are unchanged; native Windows/Node 24.18 completes the packaged CLI with a 220-character TEMP in 2.4 s.
Closes#162821
Share build-scoped compile-cache ownership between the launcher and runtime. Reuse inherited namespaces, avoid redundant respawns, and retire superseded builds with best-effort seven-day and 512 MiB maintenance.
Testbox: 304 focused tests passed with one Bun-only skip; pinned changed-file checks passed. Thirty child launches used 41,544 bytes instead of 1,185,000 bytes, and same-build launch time fell from 2.46 s to 1.22 s. Persistent external-plugin source capture reuse remains outside this scoped change.
