Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).
The driver/factory/seed use 'GalaxyMxGateway' (legacy 'Galaxy' was retired),
but the AdminUI editor router, GalaxyDriverPage, address picker, identity
dropdown, the Galaxy browser/probe, and DraftValidator still keyed on 'Galaxy'.
Result: the seeded GalaxyMxGateway driver couldn't be edited ('no editor
registered'), UI-created Galaxy drivers wrote a type with no factory, and a
SystemPlatform-bound GalaxyMxGateway driver failed publish validation.
Align all stragglers to GalaxyMxGateway (+ failing-test-first DraftValidator
coverage). ShouldStub's 'Galaxy' legacy safety-net left intact.