VS Code extension: surface background activity (workflows/subagents/worktrees) so users don't collide with the agent

Feature request

When Claude Code (VS Code extension) runs long-lived background work — multi-agent workflows, background subagents, git worktrees it created for isolated branch work — the user has no ambient indication that anything is running or where it is operating.

Real scenario from today: a multi-hour roadmap session had (a) a 7-agent workflow filing GitHub issues in the background, (b) doc PRs being prepared in scratchpad git worktrees. The user — unaware anything was in flight — switched branches and pulled in the same repo, then apologized for "creating more work," assuming they had clobbered the agent. They hadn't (worktrees isolated everything), but they had no way to know that.

What would help

• A persistent status indicator in the extension (status bar / panel badge): N background tasks running, with names — e.g. "workflow: kl-initiative-buildout (File phase, 5/7 agents done)".
• Hover/click → the live progress tree that /workflows shows in the CLI.
• A lightweight signal when the agent is using git worktrees or holds uncommitted state tied to the repo the user is editing — even just "agent has 1 active worktree under /tmp (branch: roadmap-strategy-docs)" — so branch switches/pulls don't feel dangerous.
• Optional toast on background task completion when the user is in another editor tab.

The CLI communicates this reasonably via inline updates; the VS Code surface loses it entirely once the user clicks away from the chat panel.

🤖 Filed by Claude Code on the user's behalf