Recursion guard and static klammer checking

A klammer that reaches itself, directly or through a cycle, expanded
until the C++ stack was exhausted: the process died from SIGSEGV with no
message and no location. The former limit guarded only the top-level
fixed-point iteration, never the descent through klammer application. A
depth guard now raises a recursion error naming the klammer and where it
was applied. The same loop's termination test moves from "the katom list
stopped growing" to "a pass applied no klammer", since a klammer whose
body expands to nothing is a reduction that adds no katoms; exceeding the
round limit is now an error rather than a message followed by rendering a
document with live klammers still in it.

ktext --check locates every klammer application written in a document or
in a klammer body and checks name existence, argument count, option
names, and target coverage without applying anything, reporting all
problems at once. This is possible because Klammertext has no catcodes:
katom structure is fixed when a file is read, so a klammer body has a
determinate shape before it is expanded. The check therefore reaches what
the engine cannot -- the branch of a @cond that is not selected, and
bodies a given render never enters.

@cond's set of truth values is an open language question, so its meaning
is unchanged here; an unrecognized predicate now warns, giving its value
and location.

tst/ gains recursion_test.sh (7 cases) and check_test.sh (19 cases), and
this snapshot's test Makefile is generated from the shipped suite list so
the two cannot drift apart.

(from dev c27e63802406)

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tst/Makefile

@@ -1,22 +1,16 @@
 # Klammertext distribution test suite (subset).
 #
-# Runs the eight shell regression suites:
-#   cond_test.sh     — @cond argument delimitation
-#   deftype_test.sh  — the four klammer definition modes + redefinition table
-#   escape_test.sh   — target character escaping and quoted specials
-#   filename_test.sh — filenames with spaces (quoting, " / " lists, rescue)
-#   alone_test.sh    — an optional argument's three values (default, the
-#                      argument type's :alone value, a written value)
-#   modulepath_test.sh — @eval finds modules beside the file that names them
-#   klammerset_test.sh — the @@@klammerset system command and its search path
-#   editor_test.sh   — editor support (doc/edit): indentation and table
-#                      alignment; needs python3, uses Emacs when installed
+# Runs the shell regression suites shipped with this snapshot (the list is
+# generated from the distribution manifest, so it cannot drift from the files
+# actually shipped).  Each suite's own header comment says what it covers.
 #
 # Requires KLAMMERTEXT_HOME set and `ktext` on PATH (build it with `make -C com`).
 
 .PHONY: test
 test:
 	./cond_test.sh
+	./recursion_test.sh
+	./check_test.sh
 	./deftype_test.sh
 	./escape_test.sh
 	./filename_test.sh