fix(lang): the action drain is the program's; --check runs every check a build makes; a registry key named count is refused; name lookups are tables

- the function that calls every reducer (and the action queue) is written in the program's own
  file: in the first action's file it belonged to that module, depended on every module with a
  reducer, and joined a game's modules into one 69-module cycle (examples/actions/modules and a
  ludic deps case hold it); the state instances, the queue and the reducers make no deps edges
- ludicc --check / ludic build --check lower the program too and write nothing, so the code
  writer's refusals are in it: a bind to a function that is gone, an unknown name (and the checker
  now refuses fn <missing> itself); rejects bind_missing_fn, unknown_name, registry_count_key
- def R count is refused: its constant would be PREFIX_COUNT, the registry's size
- a file's module, package, trust and numbers-float are tables, and from the check on the lookups
  of functions, enums, records, globals and externs are too (tagged enums kept as a list): Maroon
  Lake's check-only build went from about 20 s to 7 s including lowering, its IR from about 2
  minutes to under 10 s; duplicate declarations are found by table, not a pair of loops
- threads.ludic's pool check gives each call a little work, so a busy machine cannot run them all
  on the caller before a worker wakes (it failed one run in three under load)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

selfhost/check/check_expr.ludic

@@ -49,6 +49,9 @@ function ck_expr(e: Node) -> pointer {
     let f = ck_fn(e.s)
     ck_vis(f, e.s, e)
     if f != null { return fn_sig_of(f) }
+    # the emitter's own refusal, here too, so a check-only build finds it (a bind to a function
+    # that is gone)
+    if find_fn(e.s) == null { ck_err("fnref", e, `fn {e.s}: no function called {e.s}`) }
     return "?"
   }
   if k == E_NEW { return ck_new(e) }