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/main.ludic

@@ -188,6 +188,7 @@ entry {
   cur_dir = dir_of(path)
   g_src_name = base_name(path)                    # for panic/expect file:line messages
   g_parse_file = path                             # for the compiler's own file:line diagnostics
+  g_act_main = path                               # 0.R: where the action drain is written
   lex(src)
   parse_program()
   g_prog_user_end = len(prog)
@@ -217,9 +218,15 @@ entry {
   check_duplicate_decls()
   g_mg_entry = path
   if g_migrate { mg_collect() }                   # 0.S2: the vars that move (migrate.ludic)
+  ix_start()                                      # the lookups by name, as tables (emit_core.ludic)
   check_program()                                 # L4: the types agree before anything is emitted
   if g_migrate { mg_finish() }
-  if g_check_only { exit(0) }                     # --check: the checks are all there is
+  # --check: every check a build makes - the emitter refuses things too (a bind to a function that is
+  # gone, an unknown name) - and nothing written
+  if g_check_only {
+    emit_program()
+    exit(0)
+  }
   emit_program()
   deps_flush()                                    # LUDIC_DEPS=<file>: the module graph (ludic deps)