Implement posix app loading (#643)

- Added POSIX desktop support for SDK builds, application packaging, and integration testing.
- Added POSIX filesystem partitions and improved application path handling.
- Added simulator support for loading and running applications dynamically.
- Improved simulator task stack handling and display startup reliability.
- Improved simulator display scaling, resizing, high-DPI support, and pointer accuracy.
- Fixed LVGL timers and input polling on POSIX. (fixes simulator with Linux on some Intel graphics platforms)
- Standardized data paths across platforms.
- Logging now works via separate task: this allows apps to write to log without it affecting their stdout (for apps that output text as relevant date for other apps, like the File Selection app)
- Fixes for app stdio

.gitignore

@@ -2,6 +2,7 @@
 .DS_Store
 
 build*/
+!.github/actions/build*/
 cmake*/
 CMakeCache.txt
 *.cbp
@@ -25,3 +26,5 @@ sdkconfig.board.*.dev
 
 .caveman.json
 .ai/mcp
+
+__pycache__