i18n: review and fix the strings added since the last translation review

Reviews the 474 strings that 27 pull requests added since the last
review, in all twelve catalogs, and fixes what the review confirmed:
wrong agreement when a placeholder takes a neutral value, plural-less
counts that read "1 sightings", terms that differ from the glossaries,
and typography the language guides set. Also applies most of the
findings earlier reviews left open.

zh-Hant is converted from zh-CN again. The new strings had been
translated separately with Taiwan vocabulary. The zh-Hant guide lists
two more characters OpenCC picks wrongly.

Three tests expected the old German and Spanish wording.

src/ui/sceneControls.test.mjs

@@ -627,7 +627,7 @@ test('Authoring PLAY uses the scene context, not the radio PLAY', async (context
   const f = fixture();
   try {
     await nextTick();
-    assert.equal(f.elements.start.textContent, 'REPROD.');
+    assert.equal(f.elements.start.textContent, 'REPRODUCIR');
   } finally {
     f.restore();
   }