enhancement: Minor UI refinements

[hantran-co]

[WIP by @imtuyethan]...

• 1. Needs to have some space at the end of the page. Otherwise, it's hard to spot Advanced Settings.

• 2. Remove Model is reloading to apply new changes

• 3. Empty space shows up on the right when i try to slide the right sidebar to the right

Screen.Recording.2025-01-21.at.9.32.09.AM.mov

• 4. Change top nav icon
  https://www.figma.com/design/DYfpMhf8qiSReKvYooBgDV/Jan-App-(3rd-version)?node-id=2912-116853&t=1DHgJ7INxp6fyHFS-4

• When users close both sidebars, the icons of Threads & Right sidebar settings should be like this:

• When they open both sidebars, the icon become the normal collapse icon:

• 5. Add tooltips for each icon, similar to tooltips for items on Ribbon:
  https://www.figma.com/design/DYfpMhf8qiSReKvYooBgDV/Jan-App-(3rd-version)?node-id=672-18796&t=1DHgJ7INxp6fyHFS-4