feat: generic BIP terminal control (Simulator BIP pill) (v3.6.0)

BIP was only reachable through the SCP81 listener; cards that use TCP for
other purposes (an applet's OPEN CHANNEL, a push trigger without HTTP OTA)
now get a generic control surface, independent of SCP81.

Server:
- /api/bip/control starts a plain BIP session in three modes: sink
  (default; a local TcpDumpServer that accepts the card's channels and only
  logs conn/sink-rx/conn-close, never answering; port 0 = ephemeral, the
  bound port is reported), passthru (dial the OPEN CHANNEL destination, TCP
  client only) and redirect (fixed host:port).
- /api/bip/status returns {owner, bip, listener}; /api/bip/log and
  /api/bip/log-clear share the BIP event log with /api/scp81/log.
- The session state is shared with the SCP81 listener and only one session
  runs at a time: _bip_session_stop() stops whichever control started it
  and the control responses report it as `replaced` (both directions,
  SCP81 <-> BIP).  State renamed _SCP81_MODE/_TARGET/_LISTENER/_LINK_EVENTS
  -> _BIP_* plus _BIP_OWNER.
- TcpDumpServer logs conn-close and counts accepted connections; stop()
  joins the accept thread so the port is really free on restart.
- The new control endpoints are blocked during test-script runs.

PWA:
- New Simulator pill BIP (after TR Config): mode select with notes,
  Host/Port rules, Start/Stop with a "replaced" notice, status line (mode,
  bound address, owner, channels), a Channels box and the shared BIP log
  (reuses the SCP81 log renderer, now showing `peer`).
- The SCP81 status line marks a session owned by the BIP pill.

Help EN/RU 8.10, docs/api.md, AGENTS; CAT_TP/UDP recorded as not
implemented.

Tests: tests/test_bip.py (9) and frontend/tests/bip.test.js (6).
600 frontend / 482 Python green; version 3.6.0; sw simple-v273.

frontend/tests/phone_tabs.test.js

@@ -31,6 +31,7 @@ const code = extractFunc(html, 'phoneSwitchSubtab') + '\n' +
 	'globalThis.tpRefresh = () => { globalThis._tp = (globalThis._tp || 0) + 1; };\n' +
 	'globalThis.esimFetchAll = () => { globalThis._esim = (globalThis._esim || 0) + 1; };\n' +
 	'globalThis.testInit = () => { globalThis._test = (globalThis._test || 0) + 1; };\n' +
+	'globalThis.bipEnter = () => { globalThis._bip = (globalThis._bip || 0) + 1; };\n' +
 	'globalThis.netStateFetch = () => { globalThis._netstate = (globalThis._netstate || 0) + 1; };\n';
 eval(code);
 
@@ -46,12 +47,14 @@ function setup() {
 	const buttons = [
 		{ dataset: { phoneSub: 'phone' }, classList: makeClassList() },
 		{ dataset: { phoneSub: 'tr' }, classList: makeClassList() },
+		{ dataset: { phoneSub: 'bip' }, classList: makeClassList() },
 		{ dataset: { phoneSub: 'esim' }, classList: makeClassList() },
 		{ dataset: { phoneSub: 'test' }, classList: makeClassList() },
 	];
 	const panels = {
 		'phone-sub-phone': { classList: makeClassList() },
 		'phone-sub-tr': { classList: makeClassList() },
+		'phone-sub-bip': { classList: makeClassList() },
 		'phone-sub-esim': { classList: makeClassList() },
 		'phone-sub-test': { classList: makeClassList() },
 	};
@@ -63,6 +66,7 @@ function setup() {
 	globalThis._stk = globalThis._events = globalThis._log = globalThis._poll = globalThis._pli = globalThis._tp = 0;
 	globalThis._esim = globalThis._netstate = 0;
 	globalThis._test = 0;
+	globalThis._bip = 0;
 	return { buttons, panels };
 }
 
@@ -78,6 +82,16 @@ test('TR Config pill shows the TR panel and renders PLI data', () => {
 	assert.strictEqual(globalThis._stk, 0);
 });
 
+test('BIP pill shows the BIP panel', () => {
+	const { buttons, panels } = setup();
+	phoneSwitchSubtab('bip');
+	assert.ok(!panels['phone-sub-bip'].classList.has('hidden'));
+	assert.ok(panels['phone-sub-phone'].classList.has('hidden'));
+	assert.strictEqual(globalThis._anchor, 'bip');
+	assert.strictEqual(globalThis._bip, 1);
+	assert.strictEqual(globalThis._stk, 0);
+});
+
 test('Phone pill shows the phone panel and renders CAT views', () => {
 	const { buttons, panels } = setup();
 	phoneSwitchSubtab('phone');