Add setting to disable terminal auto-focus in VS Code extension

Problem

When running Claude Code from an external terminal (e.g. Ghostty) with the VS Code extension connected for IDE integration, the terminal panel in VS Code pops up repeatedly during a session. This happens because the extension calls terminal.show() unconditionally after certain MCP tool operations (diff views, tab management, file operations, etc.).

There is no setting to disable this behavior. The existing VS Code setting terminal.integrated.focusAfterRun has no effect since the focus is triggered by the extension itself.

Expected behavior

A setting like claudeCode.terminalAutoFocus (default true) that can be set to false to prevent the extension from calling terminal.show() after IDE operations — especially when Claude Code is running in an external terminal rather than in VS Code's integrated terminal.

Environment

• Platform: macOS (Darwin 25.2.0, arm64)
• Terminal: Ghostty (external, not VS Code integrated terminal)
• Claude Code Extension: 2.1.34
• Claude Code preferred location: sidebar