Alpha Release: Cross-Platform Shell Prototype

v1.0.0-a

Initial alpha release of the shell project.

• Supports both Win32 and POSIX environments
• Implements basic built-in commands
• Executes programs from $PATH
• Includes redirection and pipeline support
• Uses a simple parser (no AST or interpreter)

Passes all Codecrafters POSIX tests. Windows build is functional but not fully tested yet.