- Add crt0.S assembly startup code for user mode entry point
- Create hello.php example application with basic system information output
- Add hello.yml build configuration for nano user mode executable
- Implement host.cc with system call interfaces and runtime initialization
- Add linker script for proper user mode memory layout
- Update Makefile with new user base addresses for shell and commands
- Implement posix.c with POSIX compatibility layer using system calls
- Update process.c with new user memory range constants and stack sizes
- Add syscall.S assembly wrapper for Linux system call interface
- Modify vm.c with expanded user address space mapping and cleanup
- Update vmfault.c with correct shell memory address reference