feat: single binary using bun

[designcode]

Note

Medium Risk
Touches core CLI command wiring and release automation, so regressions could break command availability or publishing/binary install flows across platforms.

Overview
Adds a Bun-compiled single-binary distribution path: introduces src/cli-binary.ts (static module loading via generated command-registry.ts) plus embedded specs (src/specs-embedded.ts) and a setSpecs() hook to avoid runtime filesystem reads.

Refactors the CLI entrypoint by extracting shared command registration/help/arg parsing/error handling into src/cli-core.ts, and rewires src/cli.ts to use it while keeping dynamic imports for the npm package.

Expands release automation to build, package, and upload multi-platform binaries (and new scripts/install.sh/scripts/install.ps1 installers) only when a new semantic-release tag is published; also updates update-notification messaging for binary installs and improves isNewerVersion to handle prerelease suffixes (with added tests).

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🎉 This PR is included in version 2.9.0 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

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