PLI date/time responses default to the host clock

Live finding (Network rejection events): the card asks the terminal for the
current date and time (PROVIDE LOCAL INFORMATION, qualifier 03) and our TR
answered "performed successfully" with no data.  TS 102 223 6.4.15 says the
terminal shall return the current date and time, and the 6.8.0 TR structure
requires the Date-Time and Time zone object (8.39) for that qualifier.

- _pli_data_hex(qual): the TR Config dictionary entry wins; when it is empty
  the date/time qualifier is answered from the host clock via _encode_scts
  (the SMS timestamp builder, TP-SCTS coding).
- _build_tr and _DefaultProactiveHandler put the command-specific data objects
  after the Result TLV per the 6.8.0 order (the POLL INTERVAL Duration echo
  too; real terminal responses pin the order: 8103010300 02028281 030100
  0402011E).
- _decode_tr decodes qualifier 03 with the same 8.39 coding (swapped
  semi-octet BCD digits, time-zone sign bit 0x08, 'FF' = unknown); it read
  plain decimal bytes and a 0x80 sign before.
- The PWA PLI dictionary codec for the date/time entry writes the same coding
  (it wrote plain hex bytes and a 0x80 sign), and the TR Config panel notes
  the empty-entry default.  sw cache simple-v351.

Tests: builder vectors (east/west/unknown zone) + dictionary override + the
empty non-date/time qualifier + the object order (PLI and POLL INTERVAL) + the
handler path + the TR decode + a frontend codec round-trip test.

frontend/index.html

@@ -1291,6 +1291,7 @@
 				<span class="text-sm text-gray-500 dark:text-slate-400" data-l10n="PROVIDE LOCAL INFORMATION response data">PROVIDE LOCAL INFORMATION response data</span>
 				<button id="pli-save-btn" data-needs="server" onclick="pysimPliSave()" class="px-2.5 py-1 text-sm rounded bg-emerald-600 text-white hover:bg-emerald-700 disabled:opacity-40 disabled:cursor-not-allowed" data-l10n="Save">Save</button>
 			</div>
+			<div class="text-xs text-gray-400 dark:text-slate-500 mb-1" data-l10n="The date/time qualifier is answered from the host clock while its entry is empty.">The date/time qualifier is answered from the host clock while its entry is empty.</div>
 			<div id="pysim-pli-dict" class="text-sm font-mono text-gray-600 dark:text-slate-400 max-h-[60vh] overflow-auto">
 				<span class="text-gray-400" data-l10n="Loading...">Loading...</span>
 			</div>
@@ -15572,32 +15573,45 @@ const PLI_CODECS = {
 	'03': { tlv: '2607',
 		decode(hex) {
 			const v = hex.replace(/\s/g, '').slice(4); if (v.length < 14) return null;
-			const yr = parseInt(v[0]+v[1])<70 ? 2000+parseInt(v[0]+v[1]) : 1900+parseInt(v[0]+v[1]);
-			const mo = parseInt(v[2]+v[3]), dy = parseInt(v[4]+v[5]);
-			const hh = parseInt(v[6]+v[7]), mm = parseInt(v[8]+v[9]), ss = parseInt(v[10]+v[11]);
-			const tz = parseInt(v[12]+v[13], 16);
-			const tzSign = (tz & 0x80) ? '-' : '+';
-			const tzH = Math.floor(((tz & 0x3F) || 0) / 4);
-			const tzM = (((tz & 0x3F) || 0) % 4) * 15;
+			// TP-SCTS coding (TS 123 040 9.2.3.11): swapped semi-octet BCD
+			// digits, time zone in quarters of an hour with the sign in 0x08,
+			// 'FF' unknown - the coding of eventDateTimeTlv / _encode_scts.
+			const b = [];
+			for (let i = 0; i < 14; i += 2) b.push(parseInt(v[i] + v[i + 1], 16));
+			const semi = x => (x & 0x0F) * 10 + (x >> 4);
+			const two = x => String(x).padStart(2, '0');
+			const yr = semi(b[0]) < 70 ? 2000 + semi(b[0]) : 1900 + semi(b[0]);
+			let tz = 'unknown';
+			if (b[6] !== 0xFF) {
+				const q = (b[6] & 0x07) * 10 + (b[6] >> 4);
+				tz = (b[6] & 0x08 ? '-' : '+') + two(q >> 2) + ':' + two((q % 4) * 15);
+			}
 			return {
-				dt: yr+'-'+(''+mo).padStart(2,'0')+'-'+(''+dy).padStart(2,'0'),
-				tm: (''+hh).padStart(2,'0')+':'+(''+mm).padStart(2,'0')+':'+(''+ss).padStart(2,'0'),
-				tz: tzSign+(''+tzH).padStart(2,'0')+':'+(''+tzM).padStart(2,'0'),
+				dt: yr + '-' + two(semi(b[1])) + '-' + two(semi(b[2])),
+				tm: two(semi(b[3])) + ':' + two(semi(b[4])) + ':' + two(semi(b[5])),
+				tz: tz,
 			};
 		},
 		encode(v) {
 			const dt = (v.dt||'2000-01-01').split('-'), tm = (v.tm||'00:00:00').split(':');
+			const semi = x => (((x % 10) << 4) | Math.floor(x / 10)) & 0xFF;
+			const hx = x => x.toString(16).padStart(2, '0');
 			let tzQ = 0;
 			const tzM = v.tz ? v.tz.match(/^([-+])(\d{2}):?(\d{2})$/) : null;
-			if (tzM) { const h = parseInt(tzM[2])||0, m = parseInt(tzM[3])||0; tzQ = h*4 + Math.floor(m/15); if (tzM[1]==='-') tzQ |= 0x80; }
+			if (tzM) {
+				// quarters of an hour, swapped digits + the 0x08 sign bit
+				const q = Math.min(62, (parseInt(tzM[2]) || 0) * 4 +
+					Math.floor((parseInt(tzM[3]) || 0) / 15));
+				tzQ = semi(q) | (tzM[1] === '-' ? 0x08 : 0);
+			}
 			return '2607'
-				+ (parseInt(dt[0])%100).toString(16).padStart(2,'0')
-				+ (parseInt(dt[1])||1).toString(16).padStart(2,'0')
-				+ (parseInt(dt[2])||1).toString(16).padStart(2,'0')
-				+ (parseInt(tm[0])||0).toString(16).padStart(2,'0')
-				+ (parseInt(tm[1])||0).toString(16).padStart(2,'0')
-				+ (parseInt(tm[2])||0).toString(16).padStart(2,'0')
-				+ tzQ.toString(16).padStart(2,'0');
+				+ hx(semi((parseInt(dt[0], 10) || 0) % 100))
+				+ hx(semi(parseInt(dt[1], 10) || 1))
+				+ hx(semi(parseInt(dt[2], 10) || 1))
+				+ hx(semi(parseInt(tm[0], 10) || 0))
+				+ hx(semi(parseInt(tm[1], 10) || 0))
+				+ hx(semi(parseInt(tm[2], 10) || 0))
+				+ hx(tzQ);
 		},
 		fields: [
 			{id:'dt',label:'Date',type:'date'},{id:'tm',label:'Time',type:'time'},
@@ -19941,6 +19955,7 @@ const LANG_RU = {
 	'No further info can be given': 'Дополнительная информация отсутствует',
 	'Link dropped (network failure or user cancellation)': 'Линия разорвана (сбой сети или отмена пользователем)',
 	'PROVIDE LOCAL INFORMATION response data': 'Данные для PROVIDE LOCAL INFORMATION',
+	'The date/time qualifier is answered from the host clock while its entry is empty.': 'Квалификатор «дата и время» при пустой записи отвечается с часов хоста.',
 	'Send STATUS': 'Отправить STATUS',
 	'help': 'справка',
 	'STATUS and Polling': 'STATUS и опрос',