Feature request: Session history tab bar in VSCode extension instead of clock icon menu

Summary

Add a tab bar or breadcrumb-style history navigator at the top of the Claude Code chat panel in the VSCode extension, replacing or supplementing the current clock icon dropdown for navigating session history.

Motivation

Switching between recent sessions currently requires clicking the clock icon to reveal a dropdown list. This is a hidden, non-discoverable interaction — users have to know the icon exists to use it.

A persistent tab bar or history strip at the top of the panel would make session history:

• Visible — always present, no hunting for an icon
• Faster — one click to switch vs. icon → dropdown → select
• Familiar — matches the tab navigation pattern used throughout VSCode

Proposed behavior

• A horizontal tab strip or recent-sessions bar appears at the top of the Claude Code chat panel
• Each entry shows the session title (or truncated first message)
• Clicking a tab switches to that session
• The clock icon / full history list can remain for accessing older sessions beyond what fits in the strip

Example

[UT-3060 rename Menu…] [UT-3059 sticky side…] [UT-3058 button…]  🕐
^--- tab strip (recent)                                           ^--- full history

This mirrors how browser tabs and VSCode's own editor tabs work, making it immediately intuitive.