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• I have searched existing issues and pull requests (including closed ones) to ensure this isn't a duplicate
• I have read CONTRIBUTING.md

Human Written Description

This addresses the review comments from @pinage404 on #778. The Nix build was using patchShebangs + nodejs when it only needed to fix two shebangs (tsc and vite), and was using the full store path for bun. Comments added for explanations in some areas too.

Related Issues/Discussions

Follow-up to #778 (review comments)

Community Feedback

@pinage404 left 5 review comments on #778 that were merged without being addressed. This PR resolves them:

1. Add comment explaining platform restriction — no longer applicable, PR fix(nix): fix ALSA mismatch, add GStreamer plugins, and repair UI environment #787 added aarch64-linux to supportedSystems
2. Remove nodejs dependency — replaced patchShebangs with targeted substituteInPlace
3. Use bun for shebangs instead of node — tsc/vite shebangs now point to bun
4. Use bun run build instead of ${pkgs.bun}/bin/bun run build — bun is already on PATH
5. Add comment explaining doCheck = false — documents sandbox limitations

Testing

• nix build .#handy completes successfully
• result/bin/handy binary exists and is executable
• ldd result/bin/handy — all shared libraries resolve
• nix path-info -r .#handy | grep -i node — returns nothing (nodejs not in closure)

Screenshots/Videos (if applicable)

N/A

AI Assistance

• No AI was used in this PR
• AI was used (please describe below)

If AI was used:

• Tools used: Claude Code
• How extensively: AI applied the changes to flake.nix and ran the nix build verification. Human directed which review comments to address and reviewed the approach.