v3.18.4: run-log review follow-ups (one ENVELOPE line per event step)

The review of v3.18.3 found the event steps logging twice: the shared sender
writes its generic `ENVELOPE(Event Download): type=... data=...` /
`ENVELOPE SW: ...` pair, and the runner's step-annotated line repeated the
same data.  `_send_event_download` gained `log=True`; the runner's envelope
and event branches pass `log=False`, so an event step logs exactly one line -
the annotated one, which already carries the step number, the event name,
the effective source and the response SW.  All other callers keep their
output unchanged (netsim, the interactive event form, the BIP/timer paths).

The review's test-pinning gaps are closed:
- the shared sender's per-segment answer line
  (`OTA SEND: ENVELOPE i/N -> <SW>`) is asserted in the multi-segment test;
- the scp80 step's report `sent` C-APDU/SP is asserted in the run-log test;
- the single-ENVELOPE-line behaviour (and the source override) is asserted
  in the event-action test.

Tests: 816 frontend + 718 Python; sw cache simple-v386.

pysim_simple_server/server.py

@@ -34,7 +34,7 @@ from osmocom.tlv import BER_TLV_IE
 from osmocom.utils import rpad
 
 
-VERSION = '3.18.3'
+VERSION = '3.18.4'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE
 
@@ -4652,11 +4652,14 @@ _EVENT_INNER_MAX = 252
 _EVENT_DATA_MAX = _EVENT_INNER_MAX - 8
 
 
-def _send_event_download(scc, event_type, event_data=None, drain=True, src=None):
+def _send_event_download(scc, event_type, event_data=None, drain=True, src=None,
+                         log=True):
     """Send ENVELOPE(Event Download) for the given event type.
     Builds: CLA C2 0000 Lc  D6 [len] (99 01 [type] 82 02 <src> 81 [extra]).
     `src` is the source device identity (TS 102 223 8.7: '82' terminal,
-    '83' network); the default is the terminal."""
+    '83' network); the default is the terminal.  `log=False` suppresses the
+    generic ENVELOPE lines - the test runner logs its own step-annotated line
+    with the event name, the source and the response SW."""
     if event_data and len(event_data) > _EVENT_DATA_MAX:
         raise ValueError('event data does not fit one ENVELOPE (max %d bytes; '
                          'chained delivery is not implemented)' % _EVENT_DATA_MAX)
@@ -4679,12 +4682,14 @@ def _send_event_download(scc, event_type, event_data=None, drain=True, src=None)
         # read as a long-form indicator)
         d6_tlv = bytes([0xD6, 0x81, len(inner)]) + bytes(inner)
     env_hex = '%sc20000%02x%s' % (scc.cat_cla, len(d6_tlv), d6_tlv.hex())
-    sys.stderr.write('ENVELOPE(Event Download): type=0x%02x data=%s\n' % (event_type, event_data.hex() if event_data else '(none)'))
+    if log:
+        sys.stderr.write('ENVELOPE(Event Download): type=0x%02x data=%s\n' % (event_type, event_data.hex() if event_data else '(none)'))
     data, sw = scc._tp.send_apdu(env_hex)
     if sw.startswith('61'):
         get_len = int(sw[2:], 16) if len(sw) == 4 else 0x100
         data, sw = scc._tp.send_apdu('00c00000%02x' % get_len)
-    sys.stderr.write('ENVELOPE SW: %s\n' % sw)
+    if log:
+        sys.stderr.write('ENVELOPE SW: %s\n' % sw)
     if drain and sw.startswith('91'):
         _handle_proactive_chain(scc, sw)
         sw = '9000'
@@ -5989,7 +5994,7 @@ def _test_run_action(server, step, ctx):
     if kind == 'envelope':
         data, sw = _send_event_download(scc, p['event'],
                                         bytes.fromhex(p['data']) if p['data'] else None,
-                                        drain=False, src=p.get('src'))
+                                        drain=False, src=p.get('src'), log=False)
         sent = 'ENVELOPE(Event Download) type=0x%02X' % p['event']
         _test_log('%s src=%s data=%s -> SW=%s%s'
                   % (sent, p.get('src') or '82', p['data'] or '(none)', sw or '(none)',
@@ -5998,7 +6003,7 @@ def _test_run_action(server, step, ctx):
         # The semantic event download: the builder owns the byte layout.
         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'))
+                                        drain=False, src=p.get('src'), log=False)
         sent = 'ENVELOPE(Event Download) type=0x%02X (%s) data=%s' % (
             p['event'], events.event_name(p['event']), data_hex)
         _test_log('%s src=%s -> SW=%s%s'