Width and height argtypes, kdesc --argtypes from ref/, txt @define/@left_right/@columns, kdiag --check value validation (from dev d6993110e9b3)

Also: the klammertext argtype (descriptions kept as source), txt table
wrapping and :hpos/:offset, @c between ‹ ›, txt section headings, the
ktext newline-only trim, capitalize(), and the argtype test suite.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

ref/ref.k

@@ -30,3 +30,9 @@
 
 @@unicode_examples.* ::
   @eval :cpp *KLAMMERTEXT_HOME*/ref/reflect unicode_examples @ @@
+
+@@argtype_definitions.k :
+  Show the defined klammer argument types @@
+
+@@argtype_definitions.* ::
+  @eval :cpp *KLAMMERTEXT_HOME*/ref/reflect argtype_definitions @ @@