clarify platform support

PLATFORMS.md

@@ -1,18 +1,31 @@
 # EXO Platform support (partial roadmap)
 
-## Tier 1
+## Tier 1 support - tested and maintained
 
 Apple Silicon MacOS
-- M3 Ultra Mac Studio
-- M4 Pro Mac Mini
-- M5 Macbook Pro
+- Mac Studio: M3 Ultra
+- Mac Mini: M4 Pro
+- Macbook Pro: M5, M4 Max
 
-## Planned
+## Tier 2 support - checked occasionally, should run without crashing
+
+
+## Tier 3 support - minimal support and testing, but no theoretical reason it shouldnt work
+
+
+# Planned
+
+## Tier 1
 
 Linux CUDA Support
 - Nvidia DGX Spark
 
+Linux CPU Support
+
+## Tier 2
+
 Linux Vulkan Support -- depends heavily on ecosystem
 - Framework Desktop
 
-Linux CPU Support
+Linux CUDA Support -- depends heavily on ecosystem
+- Framework Desktop