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/hud.js

@@ -186,6 +186,7 @@ export class IntelHUD {
     this._el = document.getElementById('intel-hud');
     if (!this._el) return;
 
+    // i18n-ignore: sensor readout codes (MGRS, GSD, NIIRS, ONA, BAND…) and a classification banner; translated parts use t()
     this._el.innerHTML = `
       <div class="hud-sonar" aria-hidden="true"></div>
 
@@ -228,7 +229,7 @@ export class IntelHUD {
         <div class="hud-content" style="text-align:right">
           <div id="hud-gsd">GSD: --m  NIIRS: --</div>
           <div id="hud-alt">ALT: --m   SUN: --° EL</div>
-          <div id="hud-ais-vessel" class="hud-ais-vessel">AIS: --</div>
+          <div id="hud-ais-vessel" class="hud-ais-vessel">${t('AIS: --')}</div>
         </div>
         <div class="hud-bracket">┘</div>
       </div>
@@ -356,9 +357,11 @@ export class IntelHUD {
       const formatted = this._formatMGRS(mgrsStr);
       mgrsLabel = formatted;
       const el = document.getElementById('hud-mgrs');
+      // i18n-ignore: sensor readout codes, same in every language
       if (el) el.textContent = `MGRS: ${formatted}`;
     } catch {
       const el = document.getElementById('hud-mgrs');
+      // i18n-ignore: sensor readout codes, same in every language
       if (el) el.textContent = 'MGRS: ---';
     }
 
@@ -367,6 +370,7 @@ export class IntelHUD {
     if (llEl) llEl.textContent = `${latDMS} ${lonDMS}`;
     const bottomEl = document.getElementById('hud-bottom-line');
     if (bottomEl) {
+      // i18n-ignore: sensor readout codes, same in every language
       bottomEl.textContent = `MGRS: ${mgrsLabel}  LAT: ${latDMS}  LON: ${lonDMS}`;
     }
 
@@ -382,6 +386,7 @@ export class IntelHUD {
     );
     const gsdEl = document.getElementById('hud-gsd');
     if (gsdEl)
+      // i18n-ignore: sensor readout codes, same in every language
       gsdEl.textContent = `GSD: ${gsd.toFixed(2)}m  NIIRS: ${niirs.toFixed(1)}`;
 
     // Altitude — reported as height above MEAN SEA LEVEL. `altM` is the raw
@@ -394,6 +399,7 @@ export class IntelHUD {
     const altMslM = ellipsoidalToMslDisplayM(altM, geoidN);
     const sunEl = this._estimateSunElevation(latDeg, lonDeg);
     if (altEl)
+      // i18n-ignore: sensor readout codes, same in every language
       altEl.textContent = `ALT: ${Math.round(altMslM)}m   SUN: ${sunEl.toFixed(1)}° EL`;
 
     // Collection timestamp
@@ -403,6 +409,7 @@ export class IntelHUD {
       const h = String(now.getUTCHours()).padStart(2, '0');
       const m = String(now.getUTCMinutes()).padStart(2, '0');
       const s = String(now.getUTCSeconds()).padStart(2, '0');
+      // i18n-ignore: sensor readout codes, same in every language
       collEl.textContent = `COLL: ${h}:${m}:${s}Z`;
     }
 
@@ -411,6 +418,7 @@ export class IntelHUD {
     const pitchDeg = Cesium.Math.toDegrees(camera.pitch);
     const ona = Math.max(0, 90 + pitchDeg);
     const onaEl = document.getElementById('hud-ona');
+    // i18n-ignore: sensor readout codes, same in every language
     if (onaEl) onaEl.textContent = `ONA: ${ona.toFixed(1)}°`;
 
     // `altM` stays the raw ellipsoidal camera height the sensor model reads