Support Stack CLI 0.5 language servers

[konojunya]

Summary

• Support stable CLI versions >=0.4.0 <0.6.0.
• Pin published 0.5.0 archives and SHA-256 for all four native targets.
• Preserve strict rejection of unsupported versions.

Verification

• Formatting, lint, types, six unit tests, and VSIX allowlist pass.
• Real VSIX with published CLI 0.4.0 and 0.5.0 passes five integration tests each on VS Code 1.91.0 and 1.136.1.
• Marketplace publication remains separate.