Updated BaseRunner.run API

[MattBurn]

Closes Issues

Closes #235

Description

• Replaces the competing capture, silent, stdout, and stderr controls in BaseRunner.run with explicit stdout/stderr stream targets.
• Adds subprocess stream fanout support for Path, string paths, open text streams, callbacks, subprocess.PIPE capture, and multiple destinations using opi.execution.text_stream.TextStreamFanout.
• Adds immutable run result objects opi.execution.base.RunResult and opi.execution.run.SubprocessRunResult with captured output, return-code helpers.
• Deprecates stdin_str, capture, and silent in favor of stdin and stdout/stderr stream targets.
• Adds focused unit tests for capture, fanout, live callbacks, stdin, timeout handling, and invalid stream targets.

---

Release Notes

Added

• Added TextStreamFanout stream-target fanout support for subprocess stdout and stderr destinations. (Updated BaseRunner.run API #238)
• Added immutable subprocess run result objects with return-code and signal helpers. (Updated BaseRunner.run API #238)

Changed

• Changed BaseRunner.run to use explicit stdout and stderr stream targets. (Updated BaseRunner.run API #238)
• Changed BaseRunner.run to return a RunResult instead of subprocess.CompletedProcess or None. (Updated BaseRunner.run API #238)

Deprecated

• Deprecated stdin_str, capture, and silent on BaseRunner.run. (Updated BaseRunner.run API #238)

[MattBurn]

Apologies for the number of CI runs, finally figured out how nox works to check locally in the future

[timmyte]

Apologies for the number of CI runs, finally figured out how nox works to check locally in the future

Anything that could be improved in the docs to make this clearer?

[MattBurn]

I am new to nox so I did not grasp what nox was going to run in CI before pushing. I ended up using uv tool run nox which was a nice and simple way to run everything at once locally. Possibly worth adding to the development guide.