feat: GSMTAP-SIM APDU streaming for Wireshark / SIMtrace Analyser (v3.1.0)

Streams every APDU the server sends or receives as GSMTAP-SIM UDP packets,
so a live capture can be followed in Wireshark or the SIMtrace Analyser
without a hardware sniffer.  CLI-only: --gsmtap [HOST[:PORT]], default
target 127.0.0.1:4729; no UI or API.

- pysim_simple_server/gsmtap.py: 16-byte big-endian GSMTAP-SIM header
  (type 0x04, sub_type 0x00 = APDU / 0x01 = ATR) + raw APDU bytes, a
  fire-and-forget non-blocking sender that never raises into card I/O, an
  ApduTracer (a response is sent as data + SW1SW2, the wire form) and a
  fan-out tracer.  The packet layout is byte-identical to
  sigrok-iso7816-stream / simtrace2-sniff (verified against the sigrok
  module) and is what the analyser's GSMTAP receiver expects.
- __main__.py: --gsmtap option, tracer installed on the shared transport
  before the first APDU, combined with --apdu-trace via the fan-out and
  re-attached across equips (pySim nulls the tracer on every equip); one
  ATR packet per equip from _apply_equipped_card/_send_gsmtap_atr.
- start.sh/start.bat: forward their extra arguments to the server, so
  ./start.sh --gsmtap works.
- tests: packet layout, loopback UDP delivery, tracer mapping, target
  parsing, fan-out; docs (READMEs, help EN/RU, AGENTS); version 3.1.0,
  sw.js simple-v235.

frontend/help.html

@@ -546,7 +546,7 @@ start.bat           # starts the server (serves PWA + API)</pre>
 		<li><strong>Server fallback</strong> — started without reader arguments, the server itself probes for a PC/SC reader at startup (3 attempts, 2&nbsp;s apart)</li>
 		<li><strong>Serial readers</strong> — start the server manually with <code class="font-mono text-sm">-d /dev/ttyUSB0</code> (Linux)</li>
 	</ul>
-	<p class="text-sm mb-3">If no card is present, the Card reader tab shows &ldquo;No card detected&rdquo;. Insert the card — the server auto-equips it (auto-equip is on by default) — or click <strong>Equip card</strong>. The server itself starts fine with an empty reader; the absence of a card is a normal state, not an error.</p>
+	<p class="text-sm mb-3">If no card is present, the Card reader tab shows &ldquo;No card detected&rdquo;. Insert the card — the server auto-equips it (auto-equip is on by default) — or click <strong>Equip card</strong>. The server itself starts fine with an empty reader; the absence of a card is a normal state, not an error. Extra arguments given to <code class="font-mono text-sm">start.sh</code>/<code class="font-mono text-sm">start.bat</code> are passed through to the server (e.g. <code class="font-mono text-sm">./start.sh --gsmtap</code> to stream APDUs as GSMTAP-SIM packets for Wireshark / SIMtrace Analyser).</p>
 
 	<h3 id="manual-install" class="text-lg font-medium mb-2">9.6 Manual installation</h3>
 	<pre class="font-mono text-xs bg-gray-100 dark:bg-slate-800 rounded p-3 mb-3"># Create and activate a venv