Reader: visible text selection in every theme; highlights follow across translations

Selection
- Selected text uses a per-theme colour (it was nearly invisible on Dark)
- The colour picker also appears on touch screens after dragging the selection
  handles, and sits below the selection there so the system menu doesn't cover it

Highlights
- Each highlight remembers its translation and whether it covers the whole verse
- In another translation the same words are found again (ignoring case and
  punctuation); whole-verse highlights cover the whole verse; when the wording
  differs, the verse gets a small colour dot instead of marking the wrong words
- Older highlights are checked against their saved words instead of trusted
- Server keeps the new fields

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/readerMarks.js

@@ -36,6 +36,9 @@ export function cleanMarks(body) {
       };
       // The highlighted words, kept so lists of highlights can show them without loading the chapter
       if (typeof h.text === 'string' && h.text.length > 0) entry.text = h.text.slice(0, 500);
+      // Which translation the words were selected in, and whether it is a whole-verse highlight
+      if (typeof h.translation === 'string' && /^[A-Za-z0-9]{2,8}$/.test(h.translation)) entry.translation = h.translation;
+      if (h.whole === true) entry.whole = true;
       highlights.push(entry);
     }
   }