package code mode host as a managed resource

[cconger]

Why

codex-code-mode-host is a managed runtime dependency, not a user-facing entrypoint. Packaging it with entrypoint binaries and resolving it relative to the running executable made its location depend on the install format. That was especially fragile across npm, standalone, and direct Linux bundles.

The host should live with the other managed resources and be resolved through InstallContext, which already owns knowledge of the active package layout.

What changed

• Package codex-code-mode-host under codex-resources/ in canonical archives on every platform, and in the direct Linux release bundle alongside bwrap.
• Resolve the host through InstallContext. Code mode uses the in-process implementation when the active installation does not provide a managed host; it no longer uses an environment override or searches next to the Codex executable.
• Recognize directly extracted Linux bundles as an explicit install method so both the code-mode host and bwrap resolve from their codex-resources/ directory.
• Update the shell and PowerShell installers, release verification, package construction, and Python SDK artifact plumbing for the resource layout. The shell installer no longer creates a visible host symlink.
• Keep installer validation compatible with packages that placed the host under bin/, while all newly produced packages use codex-resources/.

Testing

• Added package-layout coverage for the host resource on Linux, macOS, and Windows targets.
• Added installer and Python SDK artifact tests for the new archive layout.
• Added InstallContext coverage for canonical packages, direct Linux bundles, missing resources, and Windows path normalization.
• Updated code-mode provider tests for managed-host and in-process resolution.

[chatgpt-codex-connector]

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[bolinfest]

Having logic for codex-code-mode-host in this Linux-specific block feels wrong to me. Shouldn't the logic for this be universal to all three platforms?

[cconger]

This block is for the special "legacy" codex bundle for linux where we have a tarball with the binary at the top level. I think we should probably look at deprecating this release for the codex-package for linux.