The webchat UI rendered [[reply_to_current]], [[reply_to:<id>]], and
[[audio_as_voice]] tags as literal text because extractText() passed
assistant content through without stripping inline directives.
Add stripDirectiveTags() to the UI chat layer and apply it to all three
extractText code paths (string content, content array, .text property)
for assistant messages only. Regex mirrors src/utils/directive-tags.ts.
Fixes#18079
e24e465c00