[Feature]: customize session window keep-alive duration

[velga111]

Problem statement

The session window currently has a fixed keep-alive / auto-hide timing. Users who work across multiple apps or compare information between windows may need the session window to stay available longer, while users who prefer a cleaner desktop may want it to disappear sooner.

A fixed duration makes both workflows harder:

• Longer-running reference or copy/paste workflows can be interrupted when the session window hides too quickly.
• Short, quick-query workflows can leave the session window visible longer than needed.
• Users cannot tune the behavior to their own focus and desktop-management habits.

Proposed solution

Add a user setting to customize how long the session window remains open before it auto-hides or closes after the relevant trigger condition.

Key behaviors:

• Expose a configurable session window keep-alive duration in settings.
• Support a small set of sensible presets, such as short / default / long, or a numeric duration in seconds.
• Preserve the current behavior as the default value.
• Apply the configured duration consistently to the session window lifecycle.
• If supported by the existing window model, allow an option to keep the session window open indefinitely until the user manually closes or hides it.

Alternatives considered

• Keep a fixed timeout: simple, but does not fit different desktop workflows.
• Only add a manual pin/keep-open button: useful, but still requires repeated manual action and does not solve users who simply want a different default duration.
• Always keep the session window open longer: helps some users, but makes the window feel intrusive for quick interactions.

Main area

frontend settings + session window lifecycle behavior, possibly tauri if the keep-alive timing is controlled by the desktop shell.

Risk boundaries

• AgentService or conversation runtime
• tool execution or instruction loading
• session window lifecycle / navigation behavior
• MCP integration
• database schema or migrations

Mockups, screenshots, or examples

Example setting: Session window keep-alive duration with values like Default, 15 seconds, 30 seconds, 60 seconds, and Keep open until manually closed.