Add --help CLI support and update coretrace-compiler documentation

[SizzleUnrlsd]

Summary

The coretrace-compiler binary currently does not provide a --help option and the documentation is not fully aligned with the existing/expected CLI interface.
We should add a proper --help handler to the binary and update the documentation accordingly so users can easily discover available options and usage patterns.

Tasks

• Implement a --help (and possibly -h) flag in the coretrace-compiler binary.
  • Print a clear usage message (command synopsis, required/optional arguments, and common examples).
  • Ensure the process exits with a success status code when --help is invoked.
• Review the current CLI options (existing flags, modes, inputs/outputs).
• Update the README and/or dedicated documentation files to:
  • Document all current CLI options and their meanings.
  • Include the --help usage output (or a representative excerpt).
  • Add one or two minimal examples for common workflows.
• Verify that the new --help output and the documentation stay consistent.

Acceptance Criteria

• Running coretrace-compiler --help displays a structured, readable help message.
• All documented CLI options match the actual behavior of the binary.
• The documentation clearly explains how to:
  • Invoke coretrace-compiler on a source file.
  • Select modes / relevant flags.
• CI and existing tests still pass; add a basic test for the --help behavior if applicable.