Add Martian atmosphere constant (#22884)

# Objective

- Generally hard to customize meter-based metrics for atmospheres
- Address user concerns described in issue #22882 for creating a mars
atmosphere

## Solution

- Provide a default for mars like atmospheres, a common use case for a
good base to start with.
- The values in this pull request are based on this paper:
https://www.researchgate.net/publication/380239530_Physically_Based_Real-Time_Rendering_of_Atmospheres_using_Mie_Theory
- I created a pre-computed lookup texture for the mie scattering and
enabled the use of such textures within the atmosphere's `medium`
struct. note that this is only 16kb and doesn't weigh much in the repo.
however it could be moved to an asset on the network.
- Full derivation of the texture and constants can be found in this repo
I created: https://github.com/mate-h/mars-atmo

## Testing

- Updated the atmosphere example

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## Showcase

<img width="1280" height="723" alt="Screenshot 2026-02-14 at 1 20 35 AM"
src="https://github.com/user-attachments/assets/3487c67d-ce46-428e-a62b-88f6d9accbc6"
/>
<img width="1278" height="719" alt="Screenshot 2026-02-14 at 1 18 44 AM"
src="https://github.com/user-attachments/assets/2613182d-27e6-41d6-85fd-57cf40277909"
/>
<img width="1276" height="721" alt="Screenshot 2026-02-14 at 1 17 41 AM"
src="https://github.com/user-attachments/assets/cedb8d51-74eb-4c1c-9aaf-1994f6776b88"
/>
<img width="1278" height="721" alt="Screenshot 2026-02-14 at 1 13 53 AM"
src="https://github.com/user-attachments/assets/357a6907-1012-401b-857b-107f20c24fdd"
/>
<img width="1281" height="721" alt="Screenshot 2026-02-14 at 1 12 30 AM"
src="https://github.com/user-attachments/assets/aac10fed-d06f-4fad-9057-4ea5634d7a78"
/>
<img width="1279" height="722" alt="Screenshot 2026-02-14 at 1 09 26 AM"
src="https://github.com/user-attachments/assets/7ddb3663-e6dd-413f-a771-26ae620da480"
/>

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Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: atlv <email@atlasdostal.com>