net-sim: network-condition simulation in the Phone tab (v2.5.0)

Server (pysim_simple_server/netsim.py + POST /api/net-sim):
- pure builders for the observed phone write vocabulary (UICC_NAA.md §13):
  EPSNSC (A0 TLV with KSI/KASME/counts/algo, padded to the card's FCP record
  size; invalidate-wipe and invalidate-keep-key), LOCI/PSLOCI/EPSLOCI real
  and dummy forms (PLMN kept, LAC FFFE, status 01/02), Kc/KcGPRS (9-byte
  USIM and 33-byte GSM forms, 07 invalidates), EF.SMSstatus counter bump
  (read-modify-write), CBMI/CBMIR, the Location status event (9B 01 <st>,
  with the optional 13 07 location info for normal service) and the
  AUTHENTICATE APDU (TS 31.102 7.1.2.1) with DB/DC response parsing
- scenario runner executes the recipes under _CARD_LOCK, picks the first
  existing candidate path (ADF.USIM vs DF.GSM/DF.TELECOM), reads FCP/current
  records where the format is card-specific, skips the event unless the card
  subscribed to Location status, honours the scenario toggles and returns a
  per-step log; only D6/DC, ENVELOPE and AUTHENTICATE are ever sent
- GET /api/mcc-mnc serves the optional worldwide operator list
  (--mcc-mnc-list, default <workspace>/samples/mcc-mnc-list.json): ?q=
  search and ?random=1&exclude= for roaming; the list stays out of the repo

PWA:
- Phone pill gains a 'Network simulation' fieldset: one button per scenario
  (cold boot, EPS/2G attach, service lost, limited service, roaming denied,
  churn, SMS received, CB reconfig, AUTHENTICATE), a collapsed Parameters
  block (operator search + random roaming, LAC/Cell ID/TAC/RAC, optional
  identities, toggles, churn count/delay) and a step log with SWs
- i18n EN/RU, help/README/api.md/AGENTS.md updated; version 2.5.0,
  SW cache simple-v193

Tests: tests/test_netsim.py (19), frontend/tests/netsim.test.js (3) and
html guards - 423 frontend / 280 Python, all passing

frontend/help.html

@@ -474,6 +474,19 @@
 	</ul>
 	<p class="text-sm mb-3">Values persist server-side until restart. When the card issues PLI, the server injects the dictionary values into the TERMINAL RESPONSE.</p>
 
+	<h3 id="network-simulation" class="text-lg font-medium mb-2">8.7 Network simulation</h3>
+	<p class="text-sm mb-2">Replays the write patterns a real phone performs when the network condition changes (trace study in <code class="font-mono text-sm">projects/UICC_NAA.md</code>): EPS attach, service loss / limited service, roaming denial, 2G fallback, SMS delivery, cell-broadcast reconfiguration and AUTHENTICATE. One button per scenario; the card must be equipped.</p>
+	<ul class="list-disc list-inside text-sm space-y-1 mb-3">
+		<li><strong>Cold boot</strong> — invalidate EPSNSC (KSI 07, key wiped) and dummy the location files.</li>
+		<li><strong>EPS attach / 2G attach</strong> — store a real EPS NAS context (KSI, KASME, NAS counts, algorithm) and write real LOCI/PSLOCI/EPSLOCI (2G also writes real Kc/KcGPRS).</li>
+		<li><strong>Service lost / Limited service / Roaming denied</strong> — send the Location status event (only when the card subscribed to it), invalidate EPSNSC (optionally keeping the old KASME), dummy the location files (PLMN kept, LAC <code class="font-mono text-sm">FFFE</code>, status <code class="font-mono text-sm">01</code>/<code class="font-mono text-sm">02</code>) and invalidate Kc.</li>
+		<li><strong>Churn</strong> — replay real → invalid EPSNSC records back-to-back (count and delay configurable).</li>
+		<li><strong>SMS received</strong> — bump the EF.SMSstatus counter (read-modify-write) and optionally rewrite the location files.</li>
+		<li><strong>CB reconfig</strong> — write the CBMI/CBMIR message-ID lists or clear them (all FF).</li>
+		<li><strong>AUTHENTICATE</strong> — send AUTHENTICATE (3G/EPS/5G, <code class="font-mono text-sm">00 88 00 81 22</code>) with the given or random RAND/AUTN and show the response (success <code class="font-mono text-sm">DB</code> or synchronisation failure <code class="font-mono text-sm">DC</code> with AUTS).</li>
+	</ul>
+	<p class="text-sm mb-3"><strong>Parameters</strong> (collapsed) provide the operator (searchable worldwide MCC/MNC list served from the server, plus a random roaming picker), LAC/Cell ID/TAC/RAC, optional identity values (empty = random: TMSI, GUTI, KSI, KASME, Kc, NAS counts, algorithm, RAND/AUTN), the scenario toggles and the churn count/delay. The step log lists every write, ENVELOPE and AUTHENTICATE with its SW. Only UPDATE BINARY/RECORD, ENVELOPE and AUTHENTICATE are sent — FPLMN and 5GS location files are never written (no observed phone does); the writes change the card and are visible to later snapshot comparisons.</p>
+
 </section>
 
 <section class="mb-10">