use portable if cpu-feature build fails

[RetricSu]

No description provided.

[Copilot]

Pull request overview

This PR makes the cpu-features package an optional dependency to improve compatibility with systems that lack native build tools (particularly Windows). The changes allow the CLI to gracefully fall back to portable CKB binaries when CPU feature detection is unavailable.

Key Changes

• Moved cpu-features from a regular dependency to an optional dependency
• Implemented graceful fallback using dynamic require() with try-catch error handling
• Added documentation for Windows users about potential installation issues

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/node/install.ts	Replaced static import with dynamic require() wrapped in try-catch; falls back to portable binary if cpu-features unavailable
package.json	Moved cpu-features to optionalDependencies; removed from onlyBuiltDependencies and removed @types/cpu-features from devDependencies
pnpm-lock.yaml	Updated lockfile to reflect cpu-features and its dependencies (buildcheck, nan) as optional
README.md	Added note for Windows users about optional native module compilation and performance trade-offs

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

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[RetricSu]

@copilot open a new pull request to apply review suggestions on #344

[Copilot]

@RetricSu I've opened a new pull request, #345, to work on those changes. Once the pull request is ready, I'll request review from you.