feat: low-counter guard for every SCP80/RAM operation (v3.6.58)

A cntr_low PoR verdict is not recoverable by retrying - every packet whose
counter is not above the card's is rejected again - so it now stops the
operation and is stated as plain data instead of a generic PoR error.

Server:
- _cntr_low_fields(status, cntr) -> {cntr_low, card_cntr, suggested_cntr}
  (fixed-width wrap like the counter field); carried by /api/send-ota (plus
  an 'OTA CNTR-LOW: card counter ...' log line) and by the RAM install /
  install-app / cap-compat failure responses (from the failed step);
- _send_envelope's late-PoR poll now also runs after a warning ENVELOPE
  answer (62xx/63xx - the live card answers 6200 for a low counter) and
  _send_secured_packet passes the captured PoR on, so the verdict is named
  instead of a bare 'ENVELOPE failed' (that is why it only surfaced on the
  later SPI2=0x21 query in the live log).

PWA:
- spCntrLow(res) guards every flow; the Explore routes the whole run through
  a checked sendOta(), so the paginate/expanded loops stop, no further
  packet is sent and no counter is written back (delete and Send to Card
  check it too);
- the result states the card's counter and offers 'Go to preset'
  (ramGoToPreset: opens the failed operation's preset in the Cards tab for
  editing and focuses the counter field) - nothing is written
  automatically; the operation modal carries the same notice;
- help (EN/RU) documents the guard.

sw cache simple-v331; tests: 557 Python / 714 Node.

frontend/help.html

@@ -310,7 +310,7 @@
 		<li>AES requires a replay-protected counter: SPI1 bits b5&nbsp;b4 must be <code class="font-mono text-sm">10</code> (counter higher) or <code class="font-mono text-sm">11</code> (counter +1) per TS 102 225 &sect;5.1.2/&sect;5.1.3.1</li>
 		<li>Padding byte configurable (<code class="font-mono text-sm">00</code> default, or <code class="font-mono text-sm">FF</code>)</li>
 	</ul>
-	<p class="text-sm mb-3">A &ldquo;Verify vs pySim&rdquo; button cross-checks the assembled packet against pySim&rsquo;s reference <code class="font-mono text-sm">OtaDialectSms.encode_cmd</code>. A &ldquo;Send to Card&rdquo; button delivers it via SMS-PP-DOWNLOAD ENVELOPE (when connected to the server). The 2-byte CPL prefix is transmitted whenever the packet is ciphered or carries RC/CC/DS (it is part of their input) and whenever the packet is concatenated; a single unprotected SMS keeps pySim&rsquo;s CHL-first form (TS 31.115 Table 1 NOTE). Under the packet field the app reports its size and how many SMS it takes; a packet that does not fit one SMS is sent as a <strong>concatenated</strong> download (TS 31.115 &sect;4.3) &mdash; the packet is split into SMS user-data parts (first SM 132 octets, following ones 134; the first one additionally carries the concatenation and CPI information elements) and the segments are sent in order. More than 5 segments is refused, that being the practical limit of the card&rsquo;s concatenation buffer. The returned Proof of Receipt is decoded and shown as a PoR status line (status, TAR, counter, raw PoR); the last command&rsquo;s status word and response data are filled into the <strong>R-APDU parser</strong> panel, and a successful PoR advances the replay counter and clears the packet.</p>
+	<p class="text-sm mb-3">A &ldquo;Verify vs pySim&rdquo; button cross-checks the assembled packet against pySim&rsquo;s reference <code class="font-mono text-sm">OtaDialectSms.encode_cmd</code>. A &ldquo;Send to Card&rdquo; button delivers it via SMS-PP-DOWNLOAD ENVELOPE (when connected to the server). The 2-byte CPL prefix is transmitted whenever the packet is ciphered or carries RC/CC/DS (it is part of their input) and whenever the packet is concatenated; a single unprotected SMS keeps pySim&rsquo;s CHL-first form (TS 31.115 Table 1 NOTE). Under the packet field the app reports its size and how many SMS it takes; a packet that does not fit one SMS is sent as a <strong>concatenated</strong> download (TS 31.115 &sect;4.3) &mdash; the packet is split into SMS user-data parts (first SM 132 octets, following ones 134; the first one additionally carries the concatenation and CPI information elements) and the segments are sent in order. More than 5 segments is refused, that being the practical limit of the card&rsquo;s concatenation buffer. The returned Proof of Receipt is decoded and shown as a PoR status line (status, TAR, counter, raw PoR); the last command&rsquo;s status word and response data are filled into the <strong>R-APDU parser</strong> panel, and a successful PoR advances the replay counter and clears the packet. A <strong>low-counter</strong> verdict (<code class="font-mono text-sm">cntr_low</code>, or a warning ENVELOPE answer that still carries such a PoR) is <em>not</em> recoverable by retrying: every SCP80/RAM operation stops immediately and the result states the card's counter with a <strong>Go to preset</strong> button that opens the matching preset in the Cards tab, where the counter must be raised above it &mdash; nothing is written automatically.</p>
 
 	<h3 id="ram" class="text-lg font-medium mb-2">3.2 RAM</h3>
 	<p class="mb-2">Delivers Remote Application Management operations as SCP80 secured packets via SMS-PP-DOWNLOAD ENVELOPE. The card must support SCP03 (AES or 3DES). A saved card preset from the <strong>Cards</strong> tab provides the SPI, keys, TAR, and counter (RAM uses the preset's <strong>ISD TAR</strong>, <code class="font-mono text-sm">000000</code> by default).</p>