Command line args parsing library

• We are not checking repeated scalar
• We are not handling commas properly
• We are not handling short falg concatenation
• We are not handling -ve numbers because '-' minus sign can show a new option too.
• Long single letter name may collide with short names.
• No bound checks on arity
• opt->type could be corrupted in switch case

• Implement sub-commands/commands grouping
• Testing
• Environment variable fallback (infrastructure exists but not implemented)
• Mutual exclusivity constraints (--foo and --bar can't both be set)
• Dependency constraints (--foo requires --bar to also be set)
• Custom help formatting/theming options
• Automatic short flag generation from long names
• Version flag handling (--version, -V)
• Usage examples in help output
• Grouped options in help (e.g., "Input Options:", "Output Options:")
• Custom error messages per option
• Did-you-mean suggestions for typos (--helo -> did you mean --help?)
• Option aliasing (multiple names for same option)
• Deprecation warnings for options
• Response files (@file.txt to read args from file)
• Parse from string vector (not just argc/argv)
• Better error messages with context (show where in argv the error occurred)
• Negation flags (--no-color to disable --color)
• Count flags (-vvv for verbosity level)
• Benchmark suite