feat(lang): L4 type checker between parse and emit

selfhost/check/ walks every function, the entry, tests, globals' initializers and
@On listeners with real scopes, and refuses mixed number kinds, text and numbers,
two record types, mismatched slices and fn types, wrong argument counts, wrong
returns and wrong push elements - every mix-up at once, each at its line.
LUDIC_CHECK_REPORT=1 lists them by category. pointer stays untyped (L7's).

What it found is fixed: render3d's HDR scan calling the float-bits extern f_lt
with floats; ludic.shooter's right-stick aim overflowing past half a push;
prof.ludic storing longs in []int; extern arguments now coerced to their
parameters. Text-returning runtime functions say string; Assets.ready says bool.

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

packages/ludic.render3d/prof.ludic

@@ -201,7 +201,7 @@ function prof_bake_add(us: long) -> void { if prof_on { prof_bake_us_cur = prof_
 function prof_chunk(kind: int, band: int, count: int, us: long) -> void {
   if not prof_on { return }
   if prof_chunk_us == null {
-    prof_chunk_us = new []int;  prof_chunk_kind = new []int
+    prof_chunk_us = new []long;  prof_chunk_kind = new []int
     prof_chunk_band = new []int;  prof_chunk_n = new []int
   }
   push(prof_chunk_us, us);  push(prof_chunk_kind, kind)