Add function name option for address reversal

[leo385]

Summary

Add an explicit --function option for single-address reversal.

This allows callers to provide the function name together with --address and --class, so FunctionTarget receives complete metadata even when the backend only exposes a generic symbol such as FUN_005b8f00.

This is useful for projects where source mappings already identify the real function name, but Ghidra's decompiler output still uses an autogenerated symbol.

Example

re-agent reverse --address 0x005b8f00 --class CVehicleModelInfo --function SetupCommonData

Dry-run output now includes the supplied function name:

Dry run mode — no LLM calls will be made.

Would reverse: 0x005b8f00
  Class: CVehicleModelInfo
  Function: SetupCommonData

Changes

• Add --function FUNCTION_NAME to the reverse command
• Pass the explicit function name into FunctionTarget
• Preserve explicitly supplied class/function metadata when backend symbol detection is incomplete
• Show the function name in --dry-run output
• Extend CLI tests to cover the new option

Why

For address-based reversal, the backend may return a generic symbol such as:

FUN_005b8f00

while the source project already knows the real target:

CVehicleModelInfo::SetupCommonData

Providing the function name explicitly gives the reverser more accurate source context instead of relying only on the backend symbol.

Testing

Targeted CLI test:

pytest tests/test_cli/test_main.py::test_reverse_dry_run -v

Result:

PASSED

Full CLI test file on Windows:

8 passed, 1 failed

The remaining failure is an existing Windows-specific YAML path escaping issue in test_status_no_session and is unrelated to this change.