Summary

The install/README.md had drifted from the actual contents of install/. Notably, the signed macOS .dmg GUI installer (CodeMie Connect_2.0.1_aarch64_signed.dmg) was completely undocumented, the PowerShell and shell bootstrap scripts' parameters/env-vars were only partially covered, and the example release tag was stale. This PR brings the README in sync with the folder.

Changes

• Add a new macOS Installation Wizard section covering the signed Apple-Silicon .dmg installer, plus intro/distribution-list entries (previously only the Windows wizard was documented).
• Add a full PowerShell install.ps1 parameter table (-Mode, -Version, -RegistryUrl, -ScopeRegistryUrl, -InstallRoot, -DryRun) — previously only -Version/-InstallRoot were mentioned.
• Add a full install.sh env-var table (CODEMIE_INSTALL_MODE, CODEMIE_NPM_PREFIX, CODEMIE_PACKAGE_VERSION, CODEMIE_REGISTRY_URL, CODEMIE_SCOPE_REGISTRY_URL) — previously only CODEMIE_PACKAGE_VERSION was documented.
• Refresh the stale example release tag v0.0.57 → v0.8.0 (matches package.json).
• Name the install modes (portable for Windows; auto/npm-global/user-prefix for macOS/Linux) so the two platforms' defaults read as symmetric rather than inconsistent.
• Clarify that CODEMIE_INSTALL_URL points at the directory containing install.ps1, not the file.

Testing

• No code changed — docs only (install/README.md, +59/−8).
• npm run lint clean (zero warnings).
• npm run typecheck clean.
• Grep-verified every script param/env-var in the README matches the actual scripts (install.ps1, install.sh, install.cmd).
• Stale v0.0.57 tag fully removed (0 occurrences).
• Code-reviewed via sdlc-light (2 findings fixed and re-checked).

Checklist

• Code follows project standards (Conventional Commits; docs(cli): …)
• CI expected green (doc-only; lint + typecheck verified locally)
• No merge conflicts with main (branch created from da7d0df)