extract_media() scanned the full response text without distinguishing
live delivery tags from example paths in fenced code blocks, inline code
spans, and blockquotes. This caused false positives where the agent's
explanation of MEDIA: syntax (or tool output containing example paths)
was stripped from user-visible text and the path was added to the media
delivery list.
Added _mask_protected_spans() helper that replaces protected regions
with equal-length whitespace before regex matching, preserving match
offsets. The helper skips backtick-quoted paths in MEDIA: tags to
maintain existing path extraction behavior.
Fixes#35695
3ccf4fdc6d