Release VS Code extension v0.7.15

[emil14]

Summary

• update Visual Editor to visual-editor/v0.1.1, which retries the initial program load while LSP indexing is in progress
• update the pinned LSP component to lsp/v0.1.4
• prepare extension release 0.7.15

Verification

• downloaded both locked component releases and verified their immutable tag commits and SHA-256 manifests
• npm run build with Node 24
• packaged vscode-nevalang-0.7.15.vsix and verified extension/dist/webview/index.html is present
• local Extension Host test was intentionally not run because it cannot run while the user’s normal VS Code instance is open; GitHub CI runs that isolated test.