#4604 Reduce draw distance when low on RAM

[akleshchev]

#4604 Reduce draw distance when low on RAM
Textures already affect draw distance to some extent, so decided to expand that code to cut draw distance up to two times when ram is low.
Please doublecheck logic in LLViewerTexture::updateClass()

#4604 Warn user off high settings when on low-RAM hardware
A basic ok/cancel warning that throws user to 'med+' if canceled
Please check new notification's wording.

[Copilot]

Pull Request Overview

This PR implements memory-aware graphics optimizations to handle low-RAM scenarios by reducing draw distance and warning users about high quality settings on low-memory systems.

• Dynamically reduces draw distance when system memory is low and texture discard bias is high
• Adds a user notification warning when attempting to use high graphics settings with insufficient RAM
• Modifies texture memory management to be more aggressive when system memory is critically low

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
notifications.xml	Adds new warning notification for low-memory high-quality settings
llvocache.cpp	Implements draw distance reduction based on memory constraints
llviewertexture.h	Adds new method declarations for memory budget calculations
llviewertexture.cpp	Implements memory budget factor calculation and refactors memory checking
llviewermessage.cpp	Applies memory-limited draw distance to agent updates
llfloaterpreference.h	Adds tracking for previous quality level
llfloaterpreference.cpp	Implements quality level warning logic for low-memory systems

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