fix(lang): a template inside another's hole, and integer literals past 2^31 - 1

A template literal nested in a {...} hole crashed the parser: the outer
literal ended at the inner backtick. The lexer (and ludic-fmt's) now
reads a hole as code, taking strings, chars and templates in it whole.
A decimal literal past 2147483647, or a hex one of more than eight
digits, was wrapped into a negative int; it is a long with its value
now, and giving one to an int is refused. Reseed.

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

selfhost/check/check_expr.ludic

@@ -32,7 +32,10 @@ function ck_expr(e: Node) -> pointer {
   let ex = ck_expect
   ck_expect = null
   let k = e.kind
-  if k == E_INT { return "int" }
+  if k == E_INT {
+    if e.s != null { return "long" }              # a literal past 2^31 - 1
+    return "int"
+  }
   if k == E_FLOAT {
     if is_float_file(e.file) { return "float" }
     return "fixed"