Addresses teknium1's review (#64195) finding #1: the previous PR placed
the migration inside the connection IIFE, AFTER
`resolveRemoteBackend(primaryProfileKey())`. When the preference file
was missing, `primaryProfileKey()` resolved to 'default' and the remote
branch returned immediately without ever reaching the migration. Remote-
mode users got no migration at all.
Move the call site to the top of `startHermes()`, before the connection
IIFE that reads `primaryProfileKey()`. Both remote and local branches now
flow through this path before any profile-dependent resolution, so the
migration runs on first boot regardless of mode.
The inlined implementation is replaced with a thin wrapper that builds a
`MigrationDeps` bag and delegates to `migrateActiveProfileIfMissing` from
`profile-migration.ts`. No production behavior change beyond the call-
site move.
Tests added in a separate commit.
David Metcalfe
5760c65be2