v3.22.0: the event action uses the Simulator's forms (all modelled events)

The test-script event action edited its fields as a JSON textarea and only
accepted the four events events.py builds; every other event needed the raw
envelope action with hand-copied hex.  It now renders the same EVENT_FORMS
form the Phone tab's send dialog uses, for every modelled event (29; no
release gating - a script may target another card).

- PWA: the field renderer/collector is shared (eventFormFieldsHtml /
  eventFormValues / eventFormPatternError / eventFormSrc / eventFieldGroupsUpdate);
  the Phone tab keeps its ids, its release gating and its onchange updaters,
  the step editor uses test-f-ev- ids, the generic group updater and a live
  Event data (hex) preview with the one-ENVELOPE check.  The event select
  lists all EVENT_FORMS events (the numeric keys are decimal strings -
  parseInt(k, 10)); the action stores the collected fields, the built data
  and the event's source (fixed cfg.src or the cfg.srcField input - the
  action never carried src before, so MT call / IMS registration / slices
  could not be network-sourced).  The JSON textarea is gone.
- engine: the `event` action keeps `fields` validation for the four
  server-built events (a stray data hex is ignored) and accepts the
  form-built `data` for every other event - hex-validated and checked
  against events.EVENT_DATA_MAX (244, the one-ENVELOPE budget; server.py's
  _EVENT_DATA_MAX now reads it from events.py).  The runner builds the four
  at run time (fresh host clock) and sends the stored data for the rest.
- tests: the engine's data path (accepted / missing / malformed / oversized,
  the four still fields-built), the runner sending the data (fake scc), the
  editor's collect/prefill/patterns/source (Node), the shared helpers.
  Docs: test-scripts.md, api.md, help EN/RU.  Tests: 838 frontend +
  797 Python; sw cache simple-v401.

pysim_simple_server/server.py

@@ -4885,7 +4885,7 @@ def _verify_adm(scc, app, adm_hex):
 # Chained (multi-envelope) delivery is not implemented - the slice/S-NSSAI
 # data must fit one envelope (see the help).
 _EVENT_INNER_MAX = 252
-_EVENT_DATA_MAX = _EVENT_INNER_MAX - 8
+_EVENT_DATA_MAX = events.EVENT_DATA_MAX   # = 252 - 8; events.py owns the value
 
 
 def _send_event_download(scc, event_type, event_data=None, drain=True, src=None,
@@ -6544,8 +6544,13 @@ def _test_run_action(server, step, ctx):
                   % (sent, p.get('src') or '82', p['data'] or '(none)', sw or '(none)',
                      (' RESP=%s' % data) if data else ''))
     elif kind == 'event':
-        # The semantic event download: the builder owns the byte layout.
-        data_hex = events.build(p['event'], p.get('fields') or {})
+        # The semantic event download: the server builds the events it models
+        # (run time, so the data-connection host clock is fresh); every other
+        # event carries the PWA form's built hex (validated at load).
+        if p.get('data') is not None:
+            data_hex = p['data']
+        else:
+            data_hex = events.build(p['event'], p.get('fields') or {})
         data, sw = _send_event_download(scc, p['event'], bytes.fromhex(data_hex),
                                         drain=False, src=p.get('src'), log=False)
         sent = 'ENVELOPE(Event Download) type=0x%02X (%s) data=%s' % (