Desktop app 1.1.15: cannot create a second Local (branch) session while one is running — "This project already has an active Local workspace"

Describe the bug

After the desktop app auto-updated to 1.1.15, creating a new Local (branch-type) session in a project fails whenever another Local session in that same project has a live CLI process:

Session creation failed: Failed to create session: invalid argument: This project already has an active Local workspace.

This is a behavior change. Before 1.1.15 I routinely ran several Local sessions side by side in the same project, and had done so for ~3 months.

The blocking condition appears to be a running session, not the number of workspaces: at the moment of failure the project had 74 non-archived workspace_type='branch' workspaces, and exactly one session row with is_running = 1 — the session I was actively chatting in. So the app effectively enforces "one live Local session per project", and the currently-focused session is the thing that blocks creating the next one.

Affected version

Desktop app 1.1.15 (macOS). Bundled CLI: 1.0.83-5.

Steps to reproduce the behavior

1. Open a project backed by a local checkout using Local / branch workspaces (not worktrees).
2. Start a session in it and keep it active (live CLI process).
3. Try to create another session in the same project.
4. Creation fails with invalid argument: This project already has an active Local workspace.

Expected behavior

Multiple Local sessions in the same project should be creatable concurrently, as they were in 1.1.13 / 1.1.14. If concurrent Local sessions must now be limited, the restriction should be documented and the error should say what to do about it (e.g. "stop session X first") rather than surfacing a raw invalid argument.

Additional context

Evidence that this is new in 1.1.15

Possibly related new strings in the 1.1.15 binary, which suggest this comes from a new proactive branch-warmup mechanism:

• This project already has an active Local workspace.
• Local workspace creation is still waiting for proactive warmup cleanup.
• Proactive branch warmup stopped because the shared checkout changed before the session started.
• internal error: entered unreachable code: branch workspace wait loop always returns

Why worktrees aren't a workaround here

The project in question is a personal Obsidian vault. The notes must live at one fixed path so the Obsidian app and the sessions see the same files, so Local/in-place is the only viable workspace type — a worktree would create a detached copy and break the vault. That makes "use worktrees instead" not an option, and "stop the session you're currently talking in before you can start another" a significant workflow regression for anyone using several topic-scoped sessions against one local checkout.

Environment

• macOS, Apple Silicon
• Desktop app 1.1.15, CLI 1.0.83-5

Start by reproducing the failure through create_branch_workspace with one running Local session, then inspect the 1.1.15 logs and the reported proactive branch warmup strings. Done means multiple Local sessions can be created concurrently again, or any intentional restriction is documented with an actionable error message.