Add debugging documentation and JSON output for environment discovery

[Copilot]

Users experiencing Python interpreter detection issues in VS Code lack clear instructions for running PET to generate diagnostic output that maintainers can use for troubleshooting.

Changes

Documentation

• Added "Debugging Python Environment Issues" section to README with command examples and output interpretation guide

JSON Output

• Implemented --json flag for find command to output machine-readable results
• Created JsonReporter that collects environments/managers and serializes to clean JSON
• Logging disabled in JSON mode to prevent pollution of structured output

Usage

# Human-readable output with timing/stats
pet find --list --verbose

# Machine-readable JSON for programmatic consumption
pet find --json

JSON output structure:

{
  "managers": [{"executable": "/path/to/conda", "version": "...", "tool": "Conda"}],
  "environments": [{"executable": "/path/to/python", "kind": "Conda", "version": "...", ...}]
}

The verbose flag has no effect when JSON mode is active (documented in help text).

Original prompt

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This section details on the original issue you should resolve

<issue_title>Run button not working, Python interpreter not recognized, terminal stuck on PowerShell</issue_title>
<issue_description>### Description

VS Code does not properly run Python files on my laptop.

• The Run / Play button does not work
• Python is installed and works in the system terminal
• VS Code does not recognize or persist the selected Python interpreter
• The integrated terminal always opens in PowerShell
• Reinstalling VS Code and Python did not fix the issue
• Same setup works correctly on another PC

This appears to be a VS Code editor or environment issue specific to this machine.

---

VS Code Version

Latest stable version (reinstalled multiple times)

OS Version

Windows 10 / Windows 11 (please adjust to the correct one)

Steps to Reproduce

1. Install Python
2. Install VS Code
3. Open a .py file
4. Click the Run / Play button
5. Nothing happens / Python is not recognized

Expected Behavior

Python file should run using the selected interpreter.

Actual Behavior

Run button does nothing or VS Code fails to use Python.

</issue_description>

Comments on the Issue (you are @copilot in this section)

@anthonykim1 Which version of VS Code and VS Code Python extension are you on?

Do you have environment extension installed?

Try install https://marketplace.visualstudio.com/items?itemName=ms-python.vscode-python-envs

Can you update Python extension, Python environment extension to latest and see if you can still repro?
Also add "python.useEnvironmentsExtension": true, to your settings.json.

Please file issue on https://github.com/microsoft/vscode-python-environments/issues or https://github.com/microsoft/vscode-python/issues</comment_new>
<comment_new>@anthonykim1
@eleanorjboyd I think the run button not working issue that we've seen in the past may be related to the infinite discovering Python interpreter.

@Rabea707 does setting python.locator to js change anything? </comment_new>
<comment_new>@eleanorjboyd
Could you please run the Python Environment Tool and share the output? Here’s how:

1. Open VS Code
2. Press Ctrl/Cmd+Shift+P
3. Run: Python: Run Python Environment Tool (PET) in Terminal...
4. When prompted, choose “Search all”
5. Wait until it finishes and a terminal called “Python Environment Tool” appears at the bottom
6. Copy everything printed there and paste it here (or attach it as a text file)

This will show us which environments VS Code detected and how they were resolved, which is very helpful for debugging interpreter issues 👍</comment_new>

• Fixes Run button not working, Python interpreter not recognized, terminal stuck on PowerShell #310

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[karthiknadig]

Since we don't directly use --json I can add it id we really think it is useful to debug.