Type the test environments for autocomplete

Building on the class annotations from the smoke test changes:

- The suite is generic over its environment: Framework.suite is
  @generic T : Stubs with the extension returning T, and Suite<T> passes T to
  every test function. A test file declares
  `local Suite = ... --- @type Suite<ExpRoles.TestEnv>` and env autocompletes
  from there.
- The stubs declare their recorded fields, add_player returns Stubs.Player,
  and the server is one.
- ExpRoles.TestEnv : Stubs declares the extension fields, so env.R returns
  ExpRoles.Role and env.Roles is the module.

The typing immediately paid for itself by flagging real drift in the tests,
now fixed: _script_data is package private so the env exposes script_data()
instead, the join event carries its name and tick, the assignment record type
admits is_deleted, admin_state is a file local rather than an undeclared
field, and the event assertions which indexed [1] without a nil check compare
the whole event list.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

exp_roles/test/module/holders.lua

@@ -1,5 +1,5 @@
 --- Tests for listing and printing to the players who hold a role
-local Suite = ... --- @type Suite The suite this file adds its tests to, see test/lua/framework.lua
+local Suite = ... --- @type Suite<ExpRoles.TestEnv> The suite this file adds its tests to, see test/lua/framework.lua
 local test, check, eq = Suite.test, Suite.check, Suite.eq
 
 --- alice and dave are moderators with dave offline, zed has never joined
@@ -30,7 +30,7 @@ test(".get_player_names() counts a player in both lists once", function(env)
     env.R("Regular"):assign(players.alice, { silent = true, local_only = true })
     env.Roles.receive_assignment_updates{ env.assignment("alice", { "Moderator", "Regular" }) }
 
-    local sd = env.Roles._script_data()
+    local sd = env.script_data()
     check(sd.local_players.alice ~= nil and sd.synced_players.alice ~= nil, "the role is held in both lists")
     eq(Suite.sorted(env.R("Regular"):get_player_names()), { "alice", "bob" }, "the player is counted once")
 end)