New session button (+) does not work; sessions not synced across devices

Description

Bug Report

Bug 1 — New session button (+) does not respond

The "+" button at the top-left corner of the opencode web UI does nothing when clicked. No new session is created. No error appears in the browser console.

Reproduction steps:

1. Open opencode web in a browser.
2. Click the "+" button in the top-left corner.
3. Nothing happens.

Bug 2 — Sessions not synced across devices

Sessions are stored in browser localStorage. This means sessions created on one device are invisible on another, even when connecting to the same opencode server.

Reproduction steps:

1. Open opencode web from Device A (laptop).
2. Create/use a session.
3. Open opencode web from Device B (phone) — same server, same network.
4. Session list on Device B is completely empty.

Expected behavior:

• The "+" button should immediately create a new empty session.
• Sessions should be stored server-side so that any device connected to the same opencode server sees the same sessions.

Environment

| Server hardware | STB / mini PC (ARM-based, Linux) |
| opencode web version | 1.18.3 |
| Browser PC | Google Chrome Version 150.0.7871.181 (Official Build) (64-bit) |
| Browser Mobile | Android 13 |
| Network | Local LAN (192.168.x.x) |

Plugins

No response

OpenCode version

opencode desktop 1.18.3 but me open with opencode web

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

opencode=Armbian Linux v25.05.0, pc=windows 11, mobile=android 13

Terminal

No response