[QOL] Remove keyboard shortcuts from sessions sidebar

[VooDisss]

PR for #153

PR Description:

• Removes keyboard shortcuts and their visual indicators from the sessions sidebar to improve UI clarity and ergonomics.

What Changed

• Removed session navigation shortcuts (Ctrl+Shift+[ / Ctrl+Shift+]) - Removed agent/model selector shortcuts (Ctrl+Shift+A/M/T) - Removed new session shortcut (Ctrl+Shift+N) - Cleaned up all associated UI hints and keyboard shortcut displays

Why This Change?

These hotkeys were consuming valuable screen real estate while offering minimal practical benefit. The shortcuts required uncomfortable hand positions (large hand spans) and were redundant given the existing cursor-based navigation which provides better ergonomics and discoverability.

Technical Notes

• package.json changes are dependency updates from the build process - All shortcut registrations removed from keyboard registry - Command palette cleaned up to remove associated keyboard shortcuts"

[shantur]

Thanks for PR.
It's implemented in #168