Add a constructor step to record conda-ship installation metadata #1299

Use case

A constructor-based distribution may include a prebuilt executable produced by conda-ship, such as a standalone conda executable.

The executable already knows how to bootstrap its managed prefix, including from an embedded bundle for offline installation. This issue is not about air-gapped installers or choosing a conda-ship artifact layout.

The missing integration is to record who may replace the installed executable later. For a standalone conda runtime, this is the outer executable installed by constructor, not the conda package inside its managed prefix. A later conda self update needs to know whether the runtime may replace that executable itself or whether an external installer owns it and should provide the user with an installer-specific update instruction.

Existing conda-ship interface

conda-ship provides the local v1/record-installation helper. An installer invokes the installed executable once to record these values in the existing .RUNTIME_NAME.json file:

• installation label, such as constructor
• ownership, either direct or external
• stable installed executable path
• optional update instruction for external ownership

This does not require a constructor-specific metadata format or different executable bytes.

Possible constructor integration

When a constructor-based distribution needs this, add a construct option that invokes v1/record-installation after installing the executable. If the metadata is required for correct update behavior, the invocation must be part of the installer rather than a user post-install script because user scripts can be disabled.

The first consumer should determine which constructor backends and fields are actually needed. The earlier draft in #1300 attempted SH, PKG, EXE, and MSI support without a downstream consumer and was closed.

Status

There is no concrete constructor-based consumer yet, so implementation is deferred until one has a construct file and a defined executable update model. Homebrew and Python installer detection are separate work tracked in jezdez/conda-runtime#15.