[Bug]: Session hung forever after spawning subagents

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Open a new T3Code session with Opencode provider and "Full access" mode
2. Trigger a prompt like "Spawn a subagent to read the file ~/some-other-location-outside-your-project/some-file.md and create a summary". Note that the file must be outside of the current opened project on T3Code

Expected behavior

The sub agent should report back to the parent session without asking for any additional permissions during "Full access" mode

Actual behavior

Wait a few minutes and note that it will never complete the job or timeout after 300000ms

The parent thread gets hung after spawning an OpenCode subagent, but the real problem is that the child session is waiting on an external_directory permission prompt that never surfaces in the T3 Code UI.
In my case:

• parent session: ses_1b3d21dc0ffeG71m1u2qNoSXlZ
• child session: ses_1b3d19f6fffeIxa5icm1pIrpgt
  The parent looked idle, but OpenCode logs showed the child explorer session emitted multiple permission.asked events and never received a reply

Impact

Major degradation or frequent failure

Version or commit

0.0.25-nightly.20260515.295

Environment

macOS 26.5 + Opencode 1.15.7

Logs or stack traces

OpenCode log evidence:
File:
~/.local/share/opencode/log/2026-05-21T214152.log

Relevant lines:

539: permission=external_directory ... action={"permission":"external_directory","pattern":"*","action":"ask"} evaluated
540: id=per_e4c7d26b30014G4qEQzoAFEVfa ... asking
541: bus type=permission.asked publishing


and later again:

853: permission=external_directory ... action={"permission":"external_directory","pattern":"*","action":"ask"} evaluated
854: id=per_e4c81d383001nBa06Q0YSUvuij ... asking
855: bus type=permission.asked publishing


No corresponding permission.replied event was surfaced in the UI.
Eventually the session was canceled:

860-861: session.prompt ... cancel
862: error=Aborted process

Screenshots, recordings, or supporting files

No response

Workaround

Add the files that the agent has to access inside the same project so it can see them

Start in apps/desktop by tracing how OpenCode permission.asked events from a child session reach the UI and how replies are sent. Compare this flow with the events in ~/.local/share/opencode/log/2026-05-21T214152.log, especially the external_directory entries. Done means the permission prompt appears during Full access mode and the child reports back without leaving the parent session hung.