v3.23.8: the command-grouped TERMINAL RESPONSE result list

The step editor's result select offers the full TS 102 223 8.12.0 list; the
spec's applicability table (Tables 6.1/6.2/6.3, "Proactive commands versus
possible terminal response") now groups it by the selected command: the
command-relevant values first (an <optgroup> "relevant for <command>"), the
rest after ("all other results").

The grouping is ordering-only - nothing is hidden, the manual hex entry
covers everything, and ANY (the drain's respond/first too) stays a flat list,
so a stored result always matches an option and real-card deviations remain
reachable.

TR_RESULT_BY_COMMAND is parsed from the pinned PDF (41 commands) and pinned
by frontend/tests/tr_result_by_command.json; trCommandCode() resolves the
editor's command names to their type codes (the first code per name,
matching testCommandOptions) and testFormSelect gained the optgroup support.

Tests: the map vs the parsed fixture, the grouping and the union (nothing
lost), the optgroup rendering and the call-site pin.  861 frontend + 842
Python; sw cache simple-v421.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simple-v420';
+const CACHE = 'simple-v421';
 const URLS = [
   'index.html',
   'help.html',