Move a workspace to a different project (without the lossy import round-trip)

[viet-initx]

Prior search

• I searched issues and discussions; nothing proposes moving a workspace to a different project. The adjacent request is Move a live agent session to another workspace via CLI/RPC (UI optional) #3270 ("Move a live agent session to another workspace"), which covers moving a session/tab between workspaces inside the same project, not moving a workspace itself across projects.

What's the problem

A workspace is permanently owned by the project it was created under (confirmed in the Workspaces doc: "Projects contain workspaces"). There is no API, CLI command, or UI action to reparent an existing workspace to a different project. paseo workspace create/rename/archive and the create_workspace/list_workspaces MCP tools all operate on a workspace within its original project; none accept a target project.

This gets in the way when:

• A directory/worktree was registered under the wrong project by mistake (e.g. added from the wrong cwd, or a project was later split/renamed).
• Work started as a quick one-off in a scratch project and needs to move into the real project once it proves out, without losing the workspace's session history, tabs, and diffs.
• Two projects are merged (e.g. multiple repos consolidated into a monorepo), and every workspace under the old project needs to land under the new one.

Current workaround

The only path today is Import: export/re-add the workspace's directory as a new workspace under the target project. This creates a brand-new workspace record — it does not carry over the existing session history, open tabs, or timeline; it's effectively starting over rather than moving.

Requested

Allow reparenting an existing workspace to a different project, preserving its sessions/tabs and history:

• RPC/CLI: something like workspace.project.move {workspaceId, projectId} that updates the workspace's owning project in place and emits the relevant workspace-list updates (CLI counterpart: paseo workspace move <id> --project <id>, mirroring the paseo workspace rename/archive shape).
• UI (optional): drag-and-drop a workspace row onto a different project in the sidebar, or a "Move to project…" action in the workspace's context menu.
• Validation: target project must exist; clear error otherwise. Undefined behavior if the workspace's directory isn't reachable from the target project's root should be called out (or just allowed, since a project is "any directory on a machine running the daemon").

This is the workspace-level analog of #3270 (session → workspace); together they'd let a workspace and everything inside it be relocated without the lossy import round-trip.