Python: create_harness_agent skills_paths should accept str and Path

[eavanvalkenburg]

Description

create_harness_agent has a skills_paths parameter, but its type currently appears to accept only Sequence[str] | None.

It would be more ergonomic and consistent with the lower-level skills APIs if skills_paths accepted:

• a single str
• a single pathlib.Path
• a sequence of str | pathlib.Path

For example, this should be valid without requiring str(...) conversion:

from pathlib import Path

SKILLS_DIR = Path(__file__).resolve().parent / "skills"

agent = create_harness_agent(
    client=client,
    skills_paths=SKILLS_DIR,
)

Current workaround

agent = create_harness_agent(
    client=client,
    skills_paths=[str(SKILLS_DIR)],
)

Expected behavior

create_harness_agent(skills_paths=...) should match the path ergonomics of FileSkillsSource / SkillsProvider.from_paths, which already accept str | Path | Sequence[str | Path].

Suggested type shape:

skills_paths: str | Path | Sequence[str | Path] | None = None