Hover-intent prewarm sweeps across the Bots rail spawned past the pool cap,
LRU-evicting the backend the user was about to click — an evict/respawn
cascade that made profile switching progressively slower (#91545).
- prewarmProfileBackend skips speculative spawns once every pool slot holds
an open socket; the real click still spawns on demand.
- Pool max/idle become a device preference (Settings -> Advanced), persisted
atomically in userData (pool-limits.json) and applied live over IPC; the
HERMES_DESKTOP_POOL_* env vars remain the initial fallback. Defaults are
unchanged (3 backends / 10 min idle).
Squash of the 3-commit PR #92581 branch (a00dc088c5..783899d12f) applied
via diff onto the spawn-coordinator salvage; import + constant-block
conflicts resolved so the coordinator is constructed from, and follows,
the live preference (setLimit added in the next commit).
hermes-seaeye[bot]