Plan mode: allow custom tab title and open in originating VSCode window

Feature Request

Problem

When EnterPlanMode opens a plan document in VSCode, two UX issues arise:

1. Generic tab name: The tab is always titled "Claude's Plan" regardless of what the plan is about. When working on multiple plans or revisiting earlier ones, there's no way to distinguish them by tab name.

1. Wrong window targeting: With multiple VSCode windows open, the plan tab often opens in the first/leftmost window rather than the window where the Claude Code instance that created the plan is running. This forces the user to find and drag the tab to the correct window.

Proposed Solution

1. Add an optional title parameter to EnterPlanMode — Claude could set a descriptive name (e.g., "Plan: Gatus Monitoring Setup") that becomes the editor tab title. Falls back to "Claude's Plan" if not provided.

1. Open the plan tab in the same VSCode window as the Claude Code extension instance that invoked EnterPlanMode, not the first available window.

Why This Matters

The plan mode's inline commenting feature is valuable — users can annotate and give feedback directly in the document. But with generic naming and wrong-window placement, the workflow friction pushes users toward workarounds (plain markdown files, inline conversation plans) that lose the commenting capability.

Context

• EnterPlanMode currently accepts zero parameters ({})
• The tab name and window targeting appear to be handled entirely by the VSCode extension internals
• Tested in Claude Code on VSCode with SSH remote (Unraid), March 2026