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>

mac/argument_set.cpp

@@ -414,7 +414,16 @@ Parameter_set::value_map(
     check_positional(positional, loc);
     for (size_t i = 0; i < m_positional.size(); ++i) {
         auto param = m_positional[i];
-        std::string arg = as_string(positional[i].begin(), positional[i].end(), true);
+        // A "klammertext" parameter holds Klammertext SOURCE -- the text as
+        // written, quoting carets included -- so that whoever displays it can
+        // hand it to a Machine (an @@@argtype's description, 2026-09-13).
+        // The katomizer strips the caret of a quoted special into m_text, so
+        // the plain join would turn "^@date" into "@date", which re-reads as
+        // a klammer application.  A "literal" parameter keeps the plain join:
+        // its "^" forms ARE processed (a "^@" in @c prints "@").
+        std::string arg = param.m_argtype.m_name == "klammertext"
+            ? as_source(positional[i].begin(), positional[i].end(), true)
+            : as_string(positional[i].begin(), positional[i].end(), true);
         values[param.m_name] = arg;
     }
     auto optional_values = check_optional(optional, loc);
@@ -483,7 +492,7 @@ void Parameter_set::validate(
            // A .k description is prose: collapse its source layout (line
            // breaks, continuation indentation) so it re-flows with the
            // sentence -- indented .k lines would otherwise read as verbatim.
-           << collapse_whitespace(argtype.m_desc) << "\n";
+           << collapse_whitespace(unquote_punctuation(argtype.m_desc)) << "\n";
         throw Argument_error(ss.str(), loc);
     }
 }