Fix Gemini 0.46 npm build

[adamklein]

Summary

Fixes the Gemini CLI 0.46.0 Nix build by keeping optional npm dependencies installed and disabling lifecycle scripts during the npm rebuild phase.

Details

Gemini 0.46.0 now needs optional platform packages during build, notably @esbuild/linux-x64 for bundle:browser-mcp. Using --omit=optional removes that package and causes the build to fail.

buildNpmPackage already runs npm ci --ignore-scripts, but it later runs npm rebuild separately. Adding npmRebuildFlags = [ "--ignore-scripts" ]; keeps rebuild-time lifecycle scripts from triggering the previous @vscode/vsce-sign sandbox/network failure.

Verification

nix build .#gemini-cli
./result/bin/gemini --version
# 0.46.0