Hiactor codegen lack diagnostic info

The Hiactor code generator fails to output essential debug and diagnostic information when code generation from actor.h encounters issues.

```txt
Traceback (most recent call last):
File "/usr/local/bin/hiactor_codegen/actor_codegen.py", line 188, in
process_actors(act_process_args)
File "/usr/local/bin/hiactor_codegen/actor_codegen.py", line 72, in process_actors
p.map(process_one_actor, process_args)
File "/usr/lib/python3.10/multiprocessing/pool.py", line 367, in map
return self._map_async(func, iterable, mapstar, chunksize).get()
File "/usr/lib/python3.10/multiprocessing/pool.py", line 774, in get
raise self._value
File "/usr/lib/python3.10/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/usr/lib/python3.10/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/usr/local/bin/hiactor_codegen/actor_codegen.py", line 86, in process_one_actor
traverse_actor_types(unit.cursor, arg.filepath, act_list, ns_list)
File "/usr/local/bin/hiactor_codegen/traverse.py", line 171, in traverse_actor_types
traverse_actor_types(child, filepath, act_list, ns_list)
File "/usr/local/bin/hiactor_codegen/traverse.py", line 171, in traverse_actor_types
traverse_actor_types(child, filepath, act_list, ns_list)
File "/usr/local/bin/hiactor_codegen/traverse.py", line 164, in traverse_actor_types
methods, base_info = traverse_actor_components(node)
File "/usr/local/bin/hiactor_codegen/traverse.py", line 144, in traverse_actor_components
methods.append(check_and_parse_actor_method(node.spelling, child))
File "/usr/local/bin/hiactor_codegen/traverse.py", line 107, in check_and_parse_actor_method
raise RuntimeError("The return type {} of method {} in actor class {} should be void or seastar::future!"
RuntimeError: The return type int of method do_codegen in actor class codegen_actor should be void or seastar::future!
```

Start by reproducing the code-generation failure from actor.h, then read hiactor_codegen/actor_codegen.py and hiactor_codegen/traverse.py, especially check_and_parse_actor_method. Trace how the RuntimeError is surfaced during multiprocessing and identify what diagnostic context is currently lost. Done means code-generation failures provide the essential debug and diagnostic information described by the issue.

Written by the indexing model from the issue text.