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>

sks/image/image.k

@@ -34,7 +34,7 @@
 @@image.k
   basename
   :id
-  :width.length .5w
+  :width.width .5w
   @caption_args@
   :vmargin.bool true
   @hpos_args@

sks/image/image.py

@@ -76,12 +76,16 @@ class Image(klammer_base.Klammer_base):
 
         # kutil.msg("rel: " + str(self.rel_fraction))
 
-        length,  value, ltype = kutil.parse_length("html", self.width, self.rel_fraction)
+        length,  value, ltype = kutil.parse_width("html", self.width, self.rel_fraction)
         if ltype == "w":
             percent = float(value) * 100
             result.sty(f"width: {percent}%")
-        else:
+        elif ltype == "px":
+            # The html width ATTRIBUTE takes pixels only; every other unit
+            # is a style (an attribute of "2em" was silently ignored).
             result.attr("width", length)
+        else:
+            result.sty(f"width: {length}")
 
         if self.border:
             result.cls("image_border")
@@ -124,7 +128,7 @@ class Image(klammer_base.Klammer_base):
         #if self.caption or self.number:
         #    width = "\\textwidth"
         #else:
-        width = kutil.parse_length("tex", self.width, self.rel_fraction)[0]
+        width = kutil.parse_width("tex", self.width, self.rel_fraction)[0]
         width = re.sub("px", "pt", width)
         #result = f'\\includegraphics[width={width}]{{{source}}}'
         if self.number or self.caption: