Add ability to rename and star/bookmark sessions

[tfsq]

Problem

Sessions in the sidebar cannot be renamed or bookmarked. Users have no way to:

1. Give sessions meaningful names after creation
2. Mark valuable sessions for quick access

Requested Features

1. Rename Sessions

Allow users to rename sessions directly from the sidebar. Current session titles are auto-generated and often don't reflect the actual content or purpose.

2. Star/Bookmark Sessions

Add ability to star or bookmark sessions. Starred sessions should:

• Appear in a dedicated section or be visually distinguished
• Persist across app restarts
• Be easily filterable

Use Case

Power users accumulate many sessions. Without rename/bookmark, finding valuable past conversations requires scrolling through auto-generated titles that lack context.

[DOsinga]

fixed in #6995! check the next version