[Feature] Add cross-platform global installer for latest OpenHuman release #106

Summary

Create a single, global install entrypoint that installs the latest OpenHuman release on macOS, Linux, and Windows without requiring users to manually pick artifacts.

Problem

Current installation relies on users navigating release assets and choosing platform-specific files manually. This creates friction, increases support overhead, and leads to common install mistakes.

Proposed solution

Add official install scripts that detect platform/arch, resolve the latest release, download the correct artifact, and install OpenHuman with basic verification and helpful errors.

Scope

• Provide canonical commands such as:
  • macOS/Linux: curl -fsSL <install-url> | sh
  • Windows: irm <install-url> | iex
• Detect OS + architecture (darwin/linux/windows, arm64/x64)
• Resolve latest version from GitHub releases (or latest.json where appropriate)
• Download and install the correct package/artifact for each platform
• Validate checksums/signatures where available
• Add --version, --channel (future), and --help style flags where practical
• Print clear post-install guidance (PATH, launch command, uninstall location)

Repository changes (proposal)

• scripts/install.sh (macOS/Linux)
• scripts/install.ps1 (Windows)
• Optional shared metadata mapping in scripts/install-manifest.json
• CI job to smoke-test installer logic across supported runners
• README/docs updates to make the global installer the primary install path

Acceptance criteria

• Installer command works on macOS (arm64 + x64), Linux (amd64), and Windows (x64)
• Always installs the latest stable release by default
• Graceful failures with actionable messages for unsupported environments
• Basic integrity verification is implemented/documented
• README and docs include copy-paste install commands

Out of scope

• Full package-manager distribution (brew, winget, apt, rpm) in this issue
• Auto-update daemon changes

Related

• Releases: https://github.com/tinyhumansai/openhuman/releases/latest
• Website download page: https://tinyhuman.ai/openhuman