## Context

Red and blue have inherently low perceptual luminance in APCA — pure
default Lc 45 threshold. This caused ensure_minimum_contrast to lighten
them, washing out the color to pink/lavender.

When an application explicitly specifies an RGB value via
ESC[38;2;R;G;Bm,
that color should be rendered as-is. Named and indexed colors continue
to be contrast-adjusted since they come from theme mappings



[zed-colors-before.webm](https://github.com/user-attachments/assets/1adb8c95-5dec-4744-b6f8-38f085602ef4)


[zed-colors-after.webm](https://github.com/user-attachments/assets/1968db26-9c02-48cf-9542-86a6c39899c0)


Closes: #50396 

<!-- What does this PR do, and why? How is it expected to impact users?
     Not just what changed, but what motivated it and why this approach.

Link to Linear issue (e.g., ENG-123) or GitHub issue (e.g., Closes #456)
     if one exists — helps with traceability. -->

## Self-Review Checklist

<!-- Check before requesting review: -->
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Fixed true-color render in terminal