Introduces ImageRef struct and ParseImageOSC() to parse OSC 9 image
markers (\033]9;image:path=...;alt=...\007) emitted by filters. Supports
BEL and ESC-backslash terminators, tolerates markers embedded in larger
lines, and rejects malformed or path-less markers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Mortdecai