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_scenario/module/commands/roles.lua

@@ -55,7 +55,7 @@ Commands.new("get-roles", { "exp-commands_roles.description-get" })
         end
 
         local last = #roles_formatted
-        --- @diagnostic disable-next-line nil-check
+        --- @diagnostic disable-next-line: need-check-nil
         roles_formatted[last] = roles_formatted[last][2]
 
         return Commands.status.success(response)