Session status service has get() method but no single-session HTTP endpoint

[wccyzxy]

Description

The SessionStatus.Service has a get(sessionID) method that returns a single
session's runtime status (idle/busy/retry), but no HTTP endpoint exposes it.
Currently only GET /session/status exists, which returns all non-idle statuses
as a Record<SessionID, Info>. Clients that need just one session's status have
to pull the full list and filter client-side.
Add GET /session/:sessionID/status that delegates to the existing get() method,
following the same pattern as other single-session endpoints.

Plugins

No response

OpenCode version

1.2.17

Steps to reproduce

1. Start opencode serve
2. Call GET /session/:sessionID/status
3. Get 404 Not Found (endpoint doesn't exist)
4. Only GET /session/status exists, returns all statuses with no way to query a single session

Screenshot and/or share link

No response

Operating System

Linux(Ubuntu 22.04.5)

Terminal

tmux

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• This reads as a feature request (adding a missing HTTP endpoint), but it doesn't use the [FEATURE]: title prefix and hasn't used the Feature Request template (no verification checkbox, no explanation of the problem/need from a user perspective).
• If this is intended as a bug report, the required fields (Steps to Reproduce, Operating System, Terminal) are all left as _No response_, which makes it impossible to evaluate.

Please edit this issue to either:

1. Convert it to a proper feature request by adding [FEATURE]: to the title and filling in the Feature Request template, or
2. Fill in the bug report fields with relevant context.

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be related to existing issues about /session/status. Please check:

• /session/status potentially not reporting properly #12860: /session/status potentially not reporting properly (closed bug about session status endpoint behavior)
• /session/status always empty #6447: /session/status always empty (closed issue about the same endpoint)

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

Thanks for updating the issue! It now meets our contributing guidelines — the description is clear, steps to reproduce are provided, and the OS info is included. We appreciate the improvements!