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/testscripts.test.js

@@ -258,7 +258,7 @@ test('the item text check offers contains/exact only', () => {
 test('the Simulator hosts the Test script pill and its wiring', () => {
 	assert.match(html, /data-phone-sub="test"[^>]*data-l10n="Test script"/);
 	assert.match(html, /id="phone-sub-test"/);
-	assert.match(html, /\['phone', 'tr', 'esim', 'test'\]/);
+	assert.match(html, /\['phone', 'tr', 'bip', 'esim', 'test'\]/);
 	assert.match(html, /else if \(name === 'test'\) \{\s*testInit\(\);/);
 	assert.match(html, /test: 'test-script'/);
 	assert.match(html, /testRunActive\(\) && el\.closest && !el\.closest\('#phone-sub-test'\)/);