Verbatim-safe typography, ^-punctuation quoting, full-range ^UUUU^, polyglot html

Typographic transforms (---, quote pairs, ~) no longer touch verbatim
text: @c/@code/@source_listing content and ^'...'^ spans show exactly the
characters written. "^" before any punctuation character quotes it in
every target (the apostrophe excepted: ^' opens a literal span), with the
new :resolve option on @@@target declaring per-target renderings. The
^UUUU^ code-point form accepts 4-6 hex digits, the full Unicode range.
The html output and transform spellings are polyglot (XML-valid), in
preparation for an EPUB target. New suites: transform_test, character_test
(engine), typography_test (SKS).

(from dev 07ce5ea86a0a)

tst/eval_test.sh

@@ -219,6 +219,28 @@ main = putStrLn "partial" >> exitWith (ExitFailure 3) @'
     fi
 fi
 
+echo
+echo "-- the environment can be missing: the errors name what and how --"
+# Added 2026-08-22 by the error-gallery coverage review: neither message had
+# ever been printed by a test.
+run '@eval :cpp nonexistent_gallery_lib @'
+if [ $STATUS -ne 0 ] && grep -qF "Cannot open library" "$ERRF"; then
+    pass "19. :cpp names the library it could not open"
+else
+    fail "19. exit $STATUS" "$(plain < "$ERRF" | head -2)"
+fi
+# :haskell without runghc: strip PATH so the case is deterministic whether or
+# not GHC is installed; ktext itself is invoked by absolute path (which works
+# since the 2026-08-21 construct_command_pathname fix).
+env PATH=/nonexistent "$K/bin/ktext" --klammersets none \
+    -s '@eval :haskell main = putStrLn "x" @' -d >"$OUTF" 2>"$ERRF"
+hstatus=$?
+if [ $hstatus -ne 0 ] && tr '\n' ' ' < "$ERRF" | grep -qF "requires runghc"; then
+    pass "20. :haskell without runghc says what to install"
+else
+    fail "20. exit $hstatus" "$(plain < "$ERRF" | head -2)"
+fi
+
 echo
 echo "==========="
 echo "Results: ${PASS} passed, ${FAIL} failed"