[FEATURE]: v2 Add session history tab toggle configuration with default closed

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

In OpenCode V2, the session history tab (browser-style tab history / conversation history panel) is always shown by default in the TUI. There is currently no way to configure this to be closed/hidden by default.

It would be useful to add a configuration option in cli.json under the tabs group that allows users to toggle whether the session history tab is visible on startup. The default should be closed (i.e., false), so users who prefer a clean workspace are not presented with a history panel they may not need.

Proposed configuration

{
  "tabs": {
    "history": false
  }
}

Why default should be closed

1. Clean UX: Many users prefer a minimal interface without history panels competing for screen space.
2. Consistency with other toggles: Other UI elements like session.sidebar default to auto (contextual), while some settings like animations can be disabled. Making history closed-by-default aligns with user preference for minimalism.
3. Opt-in, not opt-out: Users who want history can easily enable it in cli.json, but the default shouldn't assume everyone wants it visible.

Related existing issues

• #49361 - [FEATURE] Bring back left panel with the history of conversations
• #48635 - [FEATURE] Add browser-style tab history and recovery to the TUI 2.0
• #44681 - [FEATURE] v2 Separate New Sessions From Session Tabs

Configuration location

This would live in ~/.config/opencode/cli.json under the existing tabs group, consistent with other tab-related settings:

{
  "tabs": {
    "enabled": true,
    "scope": "cwd",
    "layout": "horizontal",
    "indicators": "status",
    "history": false
  }
}

Environment

• opencode version: v2 (latest)
• OS: Linux
• Terminal: any
• Install/channel: @opencode-ai/cli