Fix/hardcoded legacy powershell

[Charlweed]

Description

Centralize and Modernize PowerShell Command Detection
Resolves issue #12410

Overview

This PR eliminates hardcoded dependencies on legacy Windows PowerShell (powershell.exe) across the codebase and introduces a dynamic, centralized detection mechanism. By preferring modern PowerShell Core (pwsh), we resolve critical runtime failures caused by executing modern scripts in legacy environments, while maintaining backward compatibility.

Rationale & Technical Implementation Choices

1. Centralized Synchronous Detection

A new utility getPowerShellCommand() has been added to core/util/shell.ts.

• Why Synchronous (spawnSync)? Several call sites, notably core/tools/definitions/runTerminalCommand.ts, invoke the shell detection during module initialization to populate static metadata and configuration. A synchronous implementation was mandatory to prevent [object Promise] from bleeding into module-level constants.
• Performance Tradeoff: While synchronous process spawning blocks the event loop, this is an explicitly accepted tradeoff. The detection result is cached at the module level for the process lifetime. In the context of a CLI or local developer tool (which is already I/O bound), a one-time synchronous probe does not meaningfully degrade the performance profile.

2. Architectural Boundaries & Public API

• Module Isolation: The detection logic utilizing the Node.js child_process module is strictly isolated in core/util/shell.ts. This prevents Node-specific dependencies from being accidentally pulled into non-Node environments (like browser extensions or WASM contexts) that might import from the general utility barrel.
• Enforcing the Public API: Instead of allowing consumers (like the CLI extensions) to perform deep internal imports directly from core/util/shell.js, the function is re-exported via core/util/index.ts. This enforces strict encapsulation and provides a stable import path through the core package's public API.

3. Robust Test Infrastructure

• Broad Vitest Aliasing: Updated extensions/cli/vitest.config.ts with a broad core alias mapping to the source directory (../../core/src). This correctly mirrors the tsconfig.json path resolution, allowing tests to run directly against the source files via the public API without requiring tightly coupled, file-specific aliases or a prior build step.
• Interface Mocking: Tests now mock the core/util/index.js public API rather than intercepting internal execAsync or child_process calls. This makes the tests resilient to internal implementation changes and focuses verification strictly on the logic's boundaries.

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Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Tests

Verification Results

• Confirmed pwsh is correctly preferred when available on Windows.
• Confirmed safe fallback to powershell on legacy Windows environments.
• Verified zero module resolution errors during testing via the new public API alias.
• All CLI tests, including refactored clipboard utility tests, pass successfully.

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Summary by cubic

Centralizes PowerShell detection and switches Windows tooling to prefer PowerShell Core (pwsh) with a safe fallback to legacy powershell. Fixes Windows runtime issues in terminal, TTS, and clipboard flows by routing all calls through one API.

• Bug Fixes

  • Prefer pwsh on Windows; fall back to powershell when unavailable in runTerminalCommand, TTS, and clipboard utilities.
  • Improve Windows clipboard reliability using System.Windows.Forms APIs and -STA for image checks and saves.

• Refactors

  • Add getPowerShellCommand() in core/util/shell.ts (sync, cached) and re-export via core/util/index.ts.
  • Replace hardcoded powershell.exe across core and extensions/cli with getPowerShellCommand().
  • Update extensions/cli vitest.config.ts to alias core to source and adjust tests to mock the core/util/index.js public API.

^{Written for commit 5bf7d3e. Summary will update on new commits.}

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[cubic-dev-ai]

No issues found across 9 files