## Why
File images contributed zero to history and compaction token estimates and were dropped from Guardian context. This undercounted context usage and omitted image evidence from reviews.
## What changed
- Estimate file images using the fixed resized-image cost, or 10,000 patch tokens for `original` detail because file references do not expose dimensions.
- Charge file images against remote compaction and Guardian request budgets.
- Preserve file images from user messages and tool outputs through Guardian selection and delivery, and deduplicate review images by file ID.
- Apply transcript image count and byte limits to both reference types, counting file ID bytes rather than referenced file contents.
## Testing
Add coverage for file-image estimates, selection limits, delivery, and compaction retention. Extend Guardian tests to verify file-image evidence reaches reviews and uploaded original-detail images trigger reviewer-history compaction.
GitOrigin-RevId: ee024204dcbe16e277fea9347c6a4d7fc120e18d
b974893c90