Tracking Issue: manifest-driven installation outside the runtime CLI

[PsiACE]

Goal

Replace powercontext setup with release-bound platform installers. install.sh and install.ps1 own bootstrap and platform environment changes, including obtaining uv, installing PowerContext and selected host distributions, exposing executables on PATH, and recording installer-owned state. They must not require Python before bootstrap.

The installer must resolve every installation through an immutable release manifest with exact versions, artifact URLs, and checksums. latest may select a release, but it must not be the installation contract.

Parent roadmap: #1352.

Existing ownership

• Tracking Issue: deterministic Agent distributions from one canonical plugin #1405 produces deterministic host distributions; this tracker installs them.
• feat(integrations): publish a versioned capability manifest #1357 owns capability declarations. This tracker owns the release manifest and artifact integrity data.
• Tracking Issue: local Server availability and service installation #1298 owns native per-user Server service behavior. This tracker does not redefine it.
• feat: add opt-in setup for all detected local agent CLIs #1301 keeps installation inside powercontext setup; this tracker should supersede it after the RFC is accepted.

Tracking

• Record install locations, manifest schema, bootstrap trust, ownership, upgrade, failure, rollback, cross-platform conformance, and CLI deprecation in an RFC.
• Publish the runtime wheel, prebuilt host distributions, immutable manifest, and checksums from the release workflow.
• Implement install.sh for macOS and Linux and install.ps1 for Windows as first-class installers that share the release manifest and conformance fixtures.
• Keep runtime profiles separate from repeated --host selection; non-interactive installation must not infer hosts from PATH.
• Deliver the first slice for the PowerContext runtime, Codex, and Claude Code.
• Migrate the remaining maintained hosts without cloning repositories or building plugins on user machines. Preserve host-specific ownership, conflict, and rollback behavior.
• Move runtime settings to config or host-native configuration. Keep doctor read-only.
• After migration, remove powercontext setup, --source, --ref, and setup-only result types through the RFC compatibility policy.
• Cover clean machines without Python, N-1 upgrade, repeat install, non-interactive use, partial failure, ownership conflict, checksum failure, and offline bundles on supported platforms.

Completion criteria

Users can install or upgrade every maintained host from immutable release artifacts without Python already installed and without calling powercontext setup. Both installers follow the same manifest contract. Repeated runs are idempotent, host failures are isolated, and the runtime CLI contains no Agent integration installation logic.

Non-goals

• Translating the current Python setup modules line by line into shell and PowerShell.
• Requiring a Python installer engine before bootstrap.
• Regenerating host distributions owned by Tracking Issue: deterministic Agent distributions from one canonical plugin #1405.
• Redefining Server service lifecycle or runtime configuration semantics.
• Automatically installing every host detected on PATH.