Fix platform-specific default virtualenvs path for Poetry on Windows and macOS

[Copilot]

• Extract a getDefaultPoetryVirtualenvsPath() helper function in poetryUtils.ts that returns the platform-specific default path for Poetry virtualenvs
• Replace all 3 hardcoded Linux paths with the new helper
• Add unit tests for the new getDefaultPoetryVirtualenvsPath() function (7 tests, all passing)
• Revert unrelated package-lock.json changes
• Add test for getUserHomeDir() returning undefined
• Run full test suite (587 passing, 4 pending - all pre-existing)
• Run code review and CodeQL checks

Original prompt

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This section details on the original issue you should resolve

<issue_title>Poetry: Incorrect default virtualenvs path on Windows and macOS</issue_title>
<issue_description>## Problem

In poetryUtils.ts, the fallback for Poetry's virtualenvs path uses ~/.cache/pypoetry/virtualenvs on all platforms, but Windows has a different default location.

Current Code

// poetryUtils.ts L169-172
const home = getUserHomeDir();
if (home) {
    poetryVirtualenvsPath = path.join(home, '.cache', 'pypoetry', 'virtualenvs');
}

Issue

Poetry uses platform-specific default locations:

• Linux: ~/.cache/pypoetry/virtualenvs ✅
• macOS: ~/Library/Caches/pypoetry/virtualenvs
• Windows: %LOCALAPPDATA%\pypoetry\Cache\virtualenvs or %APPDATA%\pypoetry\Cache\virtualenvs

The current code hardcodes the Linux path for all platforms, causing Poetry environments to not be discovered on Windows.

PET Server Reference

The PET server correctly handles this via Platformdirs in pet-poetry/src/config.rs:

let default_cache_dir = Platformdirs::new(_APP_NAME.into(), false).user_cache_path();

Suggested Fix

Use platform-specific paths:

function getDefaultVirtualenvsPath(): string | undefined {
    const home = getUserHomeDir();
    if (!home) return undefined;
    
    if (isWindows()) {
        // Try LOCALAPPDATA first, then APPDATA
        const localAppData = process.env.LOCALAPPDATA;
        if (localAppData) {
            return path.join(localAppData, 'pypoetry', 'Cache', 'virtualenvs');
        }
        const appData = process.env.APPDATA;
        if (appData) {
            return path.join(appData, 'pypoetry', 'Cache', 'virtualenvs');
        }
    } else if (process.platform === 'darwin') {
        return path.join(home, 'Library', 'Caches', 'pypoetry', 'virtualenvs');
    }
    
    // Linux default
    return path.join(home, '.cache', 'pypoetry', 'virtualenvs');
}

Affected File

src/managers/poetry/poetryUtils.ts</issue_description>

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

• Fixes Poetry: Incorrect default virtualenvs path on Windows and macOS #1182

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[karthiknadig]

The core fix is correct and well-implemented. The new getDefaultPoetryVirtualenvsPath() function properly handles platform-specific paths for Windows, macOS, and Linux.

Note: The PR includes unrelated package-lock.json changes (adding "peer": true to many packages). Consider reverting those before merging.

cc @copilot

[karthiknadig]

Consider also testing when getUserHomeDir() returns undefined (not just empty string ''), since that's also a possible return value from that function.

@copilot

[Copilot]

Added a test for getUserHomeDir() returning undefined in 7b16f74.

[karthiknadig]

@copilot please address review comments

[Copilot]

The core fix is correct and well-implemented. The new getDefaultPoetryVirtualenvsPath() function properly handles platform-specific paths for Windows, macOS, and Linux.

Note: The PR includes ...

Reverted the unrelated package-lock.json changes in 7b16f74.