Defer need-check-nil and clean up stale suppressions

emmylua deserialises an unknown diagnostic code to a catch all that
matches no checker, so every `invisible`, `nil-check` and
`global-element` suppression was silently doing nothing. Renamed to the
emmylua codes. `name-style-check` has no equivalent and is dropped, it
was already disabled under luals.

The `get_tile` suppressions referenced an api typedef bug from 2024
which no longer reproduces.

need-check-nil is deferred rather than disabled on merit: a third of the
407 findings come from MapPosition and BoundingBox being aliased as
`struct|[double, double]`, so every `entity.position.x` reads as
possibly nil. The rest need per site knowledge of runtime invariants.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

exp_legacy/module/modules/gui/_role_updates.lua

@@ -2,6 +2,6 @@ local Gui = require("modules/exp_gui")
 local Roles = require("modules.exp_legacy.expcore.roles")
 local Event = require("modules/exp_legacy/utils/event")
 
---- @diagnostic disable invisible
+--- @diagnostic disable: access-invisible
 Event.add(Roles.events.on_role_assigned, Gui._ensure_consistency)
 Event.add(Roles.events.on_role_unassigned, Gui._ensure_consistency)