Add auto-resume option to VS Code extension on startup

Feature Request

The Claude Code VS Code extension (tested on 2.1.107) currently has no
setting or command to automatically resume the last session for a
workspace when VS Code (or the extension) starts. Users must manually
click "Past Conversations" or use /resume after every reload.

Proposed

Add a setting, e.g. claudeCode.resumeLastSessionOnStartup (boolean,
default false), that — when the extension activates for a workspace —
automatically opens the most recent session for that cwd instead of
starting a blank chat.

Alternatively, expose a command like claude-vscode.resumeLastSession
that users can bind to a keybinding or invoke from a tasks.json with
runOn: folderOpen.

Why

The CLI already supports this via claude --continue, and session logs
are already stored per project under ~/.claude/projects/<slug>/. The
extension has the data it needs; only the startup wiring is missing.

This would make long-running, multi-day tasks in the extension UI much
smoother — currently the Extension-UI advantage (diff previews, IDE
context, MCP tools) comes at the cost of losing continuity on every
VS Code restart.

Environment

• Extension: anthropic.claude-code 2.1.107
• OS: Windows 10