fix: emit wire-shaped TPDUs in the GSMTAP stream (v3.1.1)

The GSMTAP stream sent logical APDUs, so a receiver (SIMtrace Analyser,
Wireshark) flagged almost every packet: case-4 commands carried their Le
byte ('length_mismatch: excessive') and responses were headerless packets
decoded as bogus commands ('truncated').  The ATR also arrived in the
middle of the stream.

- gsmtap.py: the tracer now emits wire-shaped TPDUs, matching a hardware
  sniffer capture: case 4 -> the command without Le plus the 61XX 'bytes
  available' SW (derived from the real response length), then the data as
  a GET RESPONSE TPDU (00C00000<len> + data + SW, chunked at 255); case
  1/2/3 -> one packet cmd + data + SW; unparseable APDUs fall back to raw
  command/response packets.
- No ATR/VCC/RST/PPS events at all (no line-level access over PC/SC);
  the ATR sending helper and the server-side plumbing were removed.
- Verified by replaying the bad capture's exchanges through the new
  tracer: 116 packets, zero decoder warnings (previously nearly all).
- tests: the per-case wire forms, chunking, fallbacks; README/AGENTS
  document the wire shape and its limits; version 3.1.1, sw simple-v236.

pysim_simple_server/server.py

@@ -28,7 +28,7 @@ from osmocom.tlv import BER_TLV_IE
 from osmocom.utils import rpad
 
 
-VERSION = '3.1.0'
+VERSION = '3.1.1'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE
 
@@ -2532,34 +2532,10 @@ def _handle_card_disconnect():
     _reset_proactive_log()
 
 
-def _send_gsmtap_atr(server):
-    """Stream the card's ATR as a GSMTAP-SIM packet (--gsmtap only).
-
-    Sent at every equip so a GSMTAP receiver (SIMtrace Analyser, Wireshark)
-    has the session context before the first APDU of the new session."""
-    sender = getattr(server, 'gsmtap', None)
-    if sender is None:
-        return
-    rs = getattr(server, 'rs', None)
-    atr = None
-    if rs is not None:
-        try:
-            atr = (rs.identity or {}).get('ATR')
-        except Exception:
-            atr = None
-    if not atr:
-        return
-    try:
-        sender.send_atr(bytes.fromhex(atr))
-    except (ValueError, TypeError):
-        pass
-
-
 def _apply_equipped_card(server):
     """Common post-equip state refresh + TERMINAL PROFILE, shared by the
     /api/command equip branch and the auto-equip worker."""
     global _CARD_CONNECTED
-    _send_gsmtap_atr(server)
     server.stk_pending = None
     server.menu_active = False
     _cancel_menu_timeout()