[low] Global inlineRegistry grows without bound — PNG data is never evicted

RenderMarkers stores each image's Inline struct (including its full PNGData byte slice) in a package-level sync.Map keyed by FNV-32a hash. The registry is never cleared or bounded.

extractMarkerOverlays in writer.go looks up PNG data from the registry when resolving marker sequences, so the entries must live at least as long as the current frame. However, there is no eviction path once an image is no longer visible — every distinct tool-result image from the session accumulates indefinitely.

For typical sessions with a small number of images this is benign, but a long-running agent session that returns many distinct images (e.g. repeated screenshot tool calls) will hold all their decompressed PNG bytes in memory until the process exits.

Consider evicting entries whose IDs are no longer referenced by any active overlay, or clearing the registry when Invalidate() is called (the terminal has been reset, so cached data is stale anyway).

Valid. Replaced the unbounded sync.Map with a mutex-protected LRU capped at 128 entries, with a regression test verifying eviction. I did not clear it on Invalidate because cached transcript markers still need to resolve after a terminal reset.