App undo and fork replace reference paths with aliases

Description

In the App, undoing a prompt or selecting it in the fork dialog restores a configured @reference with the alias as its attachment path instead of the resolved reference path.

The persisted file part contains both source.text.value (for example @docs) and source.path (for example /shared/company-docs). Prompt restoration currently derives the attachment path from the visible text whenever it starts with @, so the restored prompt points to <session>/docs. Submitting it again can attach the wrong directory or fail to attach the reference.

Plugins

None

OpenCode version

dev at 9f69463f1d556af2b5b51d2efa1c04f5f544f911

Steps to reproduce

1. Configure a reference alias whose resolved directory is outside the active project, such as docs -> /shared/company-docs.
2. In the App, submit a prompt containing the selected @docs reference.
3. Undo that prompt, or open the fork dialog and select it.
4. Submit the restored prompt.
5. Observe that the restored attachment path is docs, resolved under the active project, instead of /shared/company-docs.

Screenshot and/or share link

Not applicable. The failure is deterministic in extractPromptFromParts: a file part with source.text.value = "@docs", source.path = "/shared/company-docs", and session directory /repo restores with path = "docs".

Operating System

All platforms

Terminal

Not applicable (App UI)