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/templates/layer-panels.html

@@ -44,7 +44,7 @@
       </div>
       <div class="cctv-controls">
         <button id="cctv-projection-btn" class="scene-btn" data-i18n>PROJECTION ON</button>
-        <span id="cctv-quality-chip">CAL · --</span>
+        <span id="cctv-quality-chip" data-i18n-runtime>CAL · --</span>
       </div>
       <div class="cctv-calibration-block">
         <div class="cctv-calibration-header">
@@ -52,11 +52,11 @@
           <button id="cctv-adjust-btn" class="scene-btn" title="Drag the camera in the world: rings rotate, arrows move, handles set range/FOV" data-i18n-title data-i18n>ADJUST</button>
         </div>
         <div id="cctv-cal-readout" class="cctv-cal-readout" aria-label="Camera pose — click a value to type" data-i18n-aria-label>
-          <button class="cctv-cal-value" data-cal-field="heading" title="Heading (compass °) — click to type" data-i18n-title>HDG --</button>
-          <button class="cctv-cal-value" data-cal-field="pitch" title="Pitch (° up/down) — click to type" data-i18n-title>PITCH --</button>
-          <button class="cctv-cal-value" data-cal-field="fov" title="Horizontal FOV (°) — click to type" data-i18n-title>FOV --</button>
-          <button class="cctv-cal-value" data-cal-field="range" title="Range / monitor-plane distance (m) — click to type" data-i18n-title>RANGE --</button>
-          <button class="cctv-cal-value" data-cal-field="height" title="Mount height above ground (m) — click to type" data-i18n-title>HGT --</button>
+          <button class="cctv-cal-value" data-cal-field="heading" title="Heading (compass °) — click to type" data-i18n-title data-i18n-runtime>HDG --</button>
+          <button class="cctv-cal-value" data-cal-field="pitch" title="Pitch (° up/down) — click to type" data-i18n-title data-i18n-runtime>PITCH --</button>
+          <button class="cctv-cal-value" data-cal-field="fov" title="Horizontal FOV (°) — click to type" data-i18n-title data-i18n-runtime>FOV --</button>
+          <button class="cctv-cal-value" data-cal-field="range" title="Range / monitor-plane distance (m) — click to type" data-i18n-title data-i18n-runtime>RANGE --</button>
+          <button class="cctv-cal-value" data-cal-field="height" title="Mount height above ground (m) — click to type" data-i18n-title data-i18n-runtime>HGT --</button>
           <button class="cctv-cal-value" data-cal-field="north" title="North offset from catalog position (m) — click to type" data-i18n-title>ΔN --</button>
           <button class="cctv-cal-value" data-cal-field="east" title="East offset from catalog position (m) — click to type" data-i18n-title>ΔE --</button>
         </div>
@@ -78,8 +78,8 @@
       <div class="panel-header">
         <span class="panel-title" data-i18n>STREET LEVEL</span>
         <span class="panel-divider"></span>
-        <button id="sl-status" class="sl-status" type="button" aria-pressed="false" title="Turn Street Level on or off">OFF</button>
-        <button class="panel-collapse-btn" data-collapse-target="street-level-panel" title="Expand panel">◀</button>
+        <button id="sl-status" class="sl-status" type="button" aria-pressed="false" title="Turn Street Level on or off" data-i18n-title data-i18n>OFF</button>
+        <button class="panel-collapse-btn" data-collapse-target="street-level-panel" title="Expand panel" data-i18n-title>◀</button>
       </div>
       <div id="sl-body" class="sl-body">
         <div class="sl-main">
@@ -129,7 +129,7 @@
               <div class="sl-since">
                 <label class="cctv-summary-label" for="sl-since" data-i18n>SINCE</label>
                 <input id="sl-since" class="sl-range" type="range" min="0" max="8" step="1" value="0" aria-valuetext="ANY DATE" aria-describedby="sl-since-label" />
-                <output id="sl-since-label" class="sl-since-label" for="sl-since">ANY DATE</output>
+                <output id="sl-since-label" class="sl-since-label" for="sl-since" data-i18n>ANY DATE</output>
               </div>
             </fieldset>
             <ul id="sl-legend" class="sl-legend" aria-label="Coverage colours" data-i18n-aria-label></ul>