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/backend/emit_decl.ludic

@@ -213,19 +213,19 @@ function emit_test_runner() -> void {
 # two `function`s with one name would collide in the object file; say so in
 # source terms (and name both files) instead of leaving it to the IR assembler.
 function check_duplicate_fns() -> void {
+  let k = new []pointer                          # by name, in a table: a pair of loops was quadratic
+  let v = new []Node
+  ck_tab_init(k, v)
   var i = 0
   while i < len(prog) {
     let d = prog[i]
     if d.kind == N_FN {
-      var j = i + 1
-      while j < len(prog) {
-        let o = prog[j]
-        if o.kind == N_FN and (o.s == d.s) {
-          g_err_file = o.file;  g_err_line = o.line
-          perr(`function '{d.s}' is defined twice (first in {d.file}:{itoa(d.line)})`)
-        }
-        j += 1
+      let first = ck_tab_get(k, v, d.s)
+      if first != null {
+        g_err_file = d.file;  g_err_line = d.line
+        perr(`function '{d.s}' is defined twice (first in {first.file}:{itoa(first.line)})`)
       }
+      ck_tab_put(k, v, d.s, d)
     }
     i += 1
   }
@@ -240,22 +240,23 @@ function decl_group(k: int) -> int {
   return 0
 }
 function check_duplicate_decls() -> void {
+  let k = new []pointer
+  let v = new []Node
+  ck_tab_init(k, v)
   let n = g_prog_user_end
   var i = 0
   while i < n and i < len(prog) {
     let d = prog[i]
     let g = decl_group(d.kind)
     if g > 0 {
-      var j = i + 1
-      while j < n and j < len(prog) {
-        let o = prog[j]
-        if decl_group(o.kind) == g and (o.s == d.s) {
-          g_err_file = o.file
-          g_err_line = o.line
-          perr(`'{d.s}' is defined twice (first in {d.file}:{itoa(d.line)})`)
-        }
-        j += 1
+      let key = `{itoa(g)}:{d.s}`
+      let first = ck_tab_get(k, v, key)
+      if first != null {
+        g_err_file = d.file
+        g_err_line = d.line
+        perr(`'{d.s}' is defined twice (first in {first.file}:{itoa(first.line)})`)
       }
+      ck_tab_put(k, v, key, d)
     }
     i += 1
   }
@@ -264,6 +265,7 @@ function check_duplicate_decls() -> void {
 function emit_program() -> void {
   check_duplicate_fns()
   check_duplicate_decls()
+  ix_start()                                     # the lookups by name, as tables from here on
   head = buf_new()
   code = buf_new()
   g_uses_str = false