Adds a first-run Desktop choice between installing Hermes locally and
connecting to an existing remote Hermes gateway. The choice appears after
backend resolution but before ensureRuntime(), so selecting remote cannot
accidentally trigger local bootstrap.
New modules:
- first-run-setup-gate: concurrent first-run decision gate and reset semantics
- primary-backend-startup: Electron-free orchestration seam (saved remote
resolution, gate decision, remote re-resolution, local continuation)
- primary-connection-rehome: prevents dual-owner race where both cold boot()
and renderer softSwitch() could connect simultaneously
- first-run-remote-form: extracted remote form with stale-result guards
Reuses existing connection-config IPC, encrypted token storage, OAuth
session partition, and primary backend resolution.
Fixes#38602Fixes#36970
