fix: don't render bidi isolates LRI, RLI, FSI, PDI (#18942)

Skips rendering LRI, RLI, FSI, and PDI "glyphs" in the terminal.

Does not implement BIDI/RTL; that is out of scope, see #538. This is
just a hotfix to stop spamming the console with undesired character
printouts. Once BIDI support is implemented, this change will (maybe?)
no longer be necessary.

Fixes #16574.

Author: adalinesimonian

src/renderer/atlas/AtlasEngine.cpp

@@ -500,8 +500,13 @@ try
     {
         for (const auto& cluster : clusters)
         {
-            for (const auto& ch : cluster.GetText())
+            for (auto ch : cluster.GetText())
             {
+                // Render Unicode directional isolate characters (U+2066..U+2069) as zero-width spaces.
+                if (ch >= L'\u2066' && ch <= L'\u2069')
+                {
+                    ch = L'\u200B';
+                }
                 _api.bufferLine.emplace_back(ch);
                 _api.bufferLineColumn.emplace_back(columnEnd);
             }