fix(installer): make beta opt-in, default to stable channel

[riglar]

Problem

The default curl -fsSL https://get.devicecloud.dev/install.sh | sh was installing beta versions. The installer resolves the version from the proxy's /latest.json, which — until a stable release exists — synthesized the newest prerelease. With only v5.0.0-beta.* published, every default install got the beta.

Fix

Pairs with the proxy's channel support already on dev (infra get-devicecloud-dev: /latest.json → newest stable only; ?channel=beta → newest prerelease). The installers (install.sh, install.ps1) now:

• DCD_BETA — opt in to the beta channel (latest prerelease).

• DCD_VERSION — pin an exact version, e.g. for rollback (already existed; now documented as such and surfaced in guidance).

• Default installs the latest stable only. When no stable release exists yet, it errors with guidance rather than silently falling back to a beta:

  error: No stable dcd release is available yet.
    Install the latest beta:  curl -fsSL https://get.devicecloud.dev/install.sh | DCD_BETA=1 sh
    Or pin a version:         curl -fsSL https://get.devicecloud.dev/install.sh | DCD_VERSION=5.0.0-beta.1 sh
  

Precedence: DCD_VERSION > DCD_BETA > latest stable.

The manifest fetch is split from parsing so a transient network/proxy failure (curl -f non-zero) reports differently from a channel that has no release yet (HTTP 200 with "version": null).

Testing

Ran install.sh against a local mock of the proxy:

• Default (no opt-in) → strict error with the two opt-in commands, exit 1. ✓
• DCD_BETA=1 → resolves and installs 5.0.0-beta.1. ✓
• DCD_VERSION=5.0.0-beta.1 → installs the pinned version. ✓

sh -n install.sh passes. install.ps1 mirrors the same logic (pwsh unavailable locally; validated by review).

Note: the proxy serves install.sh/install.ps1 from the cli dev branch with a ~5-min cache, so this takes effect shortly after merge to dev.

🤖 Generated with Claude Code

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.