fix: resolve lint issues in vscode extension files

- Fix import order in VsCodeIde.ts (util/util before util/vscode)
- Fix negated conditions to use early returns
- Add void operator to unhandled promise calls
- Improve code clarity by using positive conditionals

These lint issues were introduced in PR #9077 and are unrelated to the
@tiptap/extension-image upgrade in this PR.

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Co-authored-by: nate <nate@continue.dev>