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/annotations/drawTool.js

@@ -198,7 +198,10 @@ export function initDrawTool({ viewer, annotations }) {
     // a limit rather than the harmless tail of a double-click.
     if (reason === 'full')
       setHint(
-        `That shape already has ${MAX_VERTICES} points — finish it or press Backspace.`,
+        t(
+          'That shape already has {count} points — finish it or press Backspace.',
+          { count: MAX_VERTICES },
+        ),
       );
     else if (reason === 'invalid')
       setHint(t('That point is off the globe — click on the world.'));
@@ -241,7 +244,11 @@ export function initDrawTool({ viewer, annotations }) {
       return result;
     } catch (error) {
       if (destroyed || attempt !== generation) return null;
-      setHint(`Could not place the shape: ${error?.message || error}`);
+      setHint(
+        t('Could not place the shape: {error}', {
+          error: error?.message || error,
+        }),
+      );
       return null;
     }
   };
@@ -325,7 +332,11 @@ export function initDrawTool({ viewer, annotations }) {
         // Somebody else is using the pointer — possibly an older instance of
         // this same tool that has not finished tearing down. Say so instead of
         // half-starting.
-        setHint(`${pointerOwner()} is using the pointer — close it first.`);
+        setHint(
+          t('{owner} is using the pointer — close it first.', {
+            owner: pointerOwner(),
+          }),
+        );
         return active;
       }
     }