refactor: restructure CLI with optimization flags and debug modes

[LunaStev]

Summary

Refactor the CLI interface to support optimization level specification and granular debug output capabilities. Improves developer experience through modularized structure and enhanced error handling.

Changes

Library Configuration

• Add library target configuration to Cargo.toml
  • Expose wavec as both binary and library
  • Specify lib.rs path explicitly

CLI Argument Parsing Refactor

• Extract commands module
  • Separate command handling into handle_run and handle_build functions
  • Introduce DebugFlags struct for modular debug output control
• Add optimization flag support: -O0, -O1, -O2, -O3, -Oz, -Ofast
• Remove verbose flag (replaced by debug modes)

Debug Output System

• --debug-wave=tokens: Display lexer token stream
• --debug-wave=ast: Show abstract syntax tree
• --debug-wave=ir: Print LLVM intermediate representation
• --debug-wave=mc: Display machine code path
• --debug-wave=hex: Dump binary in hexadecimal format
• --debug-wave=all: Enable all debug outputs

Compilation Pipeline Updates

• Pass optimization flag to clang invocation
• Thread debug flags through runner and backend
• Remove standalone CompilerConfig system

Simplify runner.rs Execution Flow

• Change from buffering to direct output
• Remove unused import resolution code
• Pass opt_flag and debug_flags to backend

Error Handling Improvements

• Add dedicated errors module
• Define CliError enum (NotEnoughArgs, UnknownCommand, MissingArgument)
• Implement Display trait for formatted error messages

Help Output Improvements

• Group commands, optimization, and debug options
• Add practical usage examples
• Remove verbose mode information

Usage Examples

# Basic execution
wavec run test.wave

# With optimization level
wavec run -O3 test.wave

# With IR debug output
wavec run --debug-wave=ir test.wave

# Maximum optimization with all debug outputs
wavec run -Ofast --debug-wave=all test.wave

Benefits

• Granular Control: Independent control over optimization levels and debug outputs
• Improved Developer Experience: Clear error messages and structured help text
• Modularity: Separated command handling and error handling for better maintainability
• Flexibility: Usable as both binary and library