feat(i18n): translate the whole interface

Mark every UI string the unmarked-text check reported (534) plus text it
cannot see (helpers, joined labels, runtime-built panels), and translate
the result to Spanish and Russian: 1,679 messages each.

- Kept on purpose, with the reason where the text lives: provider and
  product names, place and camera names, codes and units, dB values, the HUD
  terminal readouts, demo shot titles that saved projects look up by title,
  and text for AI tools and the voice model.
- Modules shared with the server or AI tools stay free of the i18n import
  (local msg); the wind reading and voice session stay English and are
  translated where the page shows them.
- npm test now runs the unmarked-text check.
- Fixes on the way: a duplicated radio privacy paragraph, the contact panel
  toggle saying Expand while open, the CSS filter mistaking & for CSS.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/ui/localSdrPresentation.js

@@ -1,10 +1,26 @@
 import { localReceiverFeedName } from '../layers/localAdsb/feedNames.js';
+import { msg, t, tn } from '../i18n/index.js';
 
 /**
  * Pure presentation of the Local RTL-SDR card in the Radio panel. Receives the
  * receiver session snapshot and returns what each control should show.
  */
 
+// Receiver status codes shown on the connection chip and the connect button.
+const STATUS_LABELS = Object.freeze({
+  idle: msg('IDLE'),
+  connecting: msg('CONNECTING'),
+  tuning: msg('TUNING'),
+  streaming: msg('STREAMING'),
+  error: msg('ERROR'),
+  unsupported: msg('UNSUPPORTED'),
+});
+
+function statusLabel(status) {
+  const key = String(status || 'idle');
+  return STATUS_LABELS[key] ? t(STATUS_LABELS[key]) : key.toUpperCase();
+}
+
 function formatGain(gain) {
   return gain === 'auto' || !Number.isFinite(gain) ? 'auto' : gain.toFixed(1);
 }
@@ -20,10 +36,15 @@ function statusText(state) {
   const iqStatus =
     state.samplesPerSecond > 0
       ? `${(state.samplesPerSecond / 1_000_000).toFixed(2)} MS/s IQ`
-      : 'waiting for IQ';
+      : t('waiting for IQ');
   const device = state.deviceLabel ? ` · ${state.deviceLabel}` : '';
   if (state.connected && !fmActive) {
-    return `${state.message}${device} · ${iqStatus} · ${state.decodedMessages} messages`;
+    const decoded = tn(
+      state.decodedMessages,
+      '{count} message',
+      '{count} messages',
+    );
+    return `${state.message}${device} · ${iqStatus} · ${decoded}`;
   }
   const detail = state.seeking
     ? state.seekMessage
@@ -31,13 +52,14 @@ function statusText(state) {
   if (state.connected && fmActive) {
     const workerStatus =
       state.workerBlocks > 0
-        ? `DSP ${state.workerBlocks} blocks`
-        : 'DSP waiting';
+        ? tn(state.workerBlocks, 'DSP {count} block', 'DSP {count} blocks')
+        : t('DSP waiting');
     const rfStatus = `RF ${formatIq(state)}`;
     const audioSignal = Number.isFinite(state.audioLevelDbfs)
-      ? `${state.audioLevelDbfs.toFixed(1)} dBFS audio`
-      : 'audio signal --';
-    return `${detail}${device} · ${iqStatus} · ${workerStatus} · ${rfStatus} · ${audioSignal} · audio ${state.audioState}`;
+      ? t('{level} dBFS audio', { level: state.audioLevelDbfs.toFixed(1) })
+      : t('audio signal --');
+    const audio = t('audio {state}', { state: state.audioState });
+    return `${detail}${device} · ${iqStatus} · ${workerStatus} · ${rfStatus} · ${audioSignal} · ${audio}`;
   }
   return detail;
 }
@@ -57,15 +79,15 @@ export function localSdrCardView(state) {
   return {
     connectionLabel: state.connected
       ? adsbActive
-        ? `${state.aircraftHeard || 0} HEARD`
-        : 'STREAMING'
-      : String(state.status || 'idle').toUpperCase(),
+        ? tn(state.aircraftHeard || 0, '{count} HEARD', '{count} HEARD')
+        : t('STREAMING')
+      : statusLabel(state.status),
     connectionActive: Boolean(state.connected),
     connectLabel: transitional
-      ? String(state.status).toUpperCase()
+      ? statusLabel(state.status)
       : state.connected
-        ? 'DISCONNECT'
-        : 'CONNECT',
+        ? t('DISCONNECT')
+        : t('CONNECT'),
     connectDisabled: transitional || !state.webUsbSupported,
     connectPressed: Boolean(state.connected),
     fmActive,
@@ -73,10 +95,10 @@ export function localSdrCardView(state) {
     modeDisabled: transitional,
     locateLabel:
       state.locationStatus === 'requesting'
-        ? 'LOCATING…'
+        ? t('LOCATING…')
         : state.locationStatus === 'ready'
-          ? 'LOCATED'
-          : 'LOCATE',
+          ? t('LOCATED')
+          : t('LOCATE'),
     locateDisabled: state.locationStatus === 'requesting',
     locateActive: state.locationStatus === 'ready',
     changeDeviceDisabled: transitional || !state.webUsbSupported,