Add setting to disable ide_opened_file auto-context from VSCode extension

The VSCode extension automatically injects an <ide_opened_file> tag with the path of the currently active editor tab on every message. This is often unrelated to what I'm asking Claude about and adds noise to the conversation, and there appears to be no way to turn it off short of closing the tab before each message.

Request: a setting (e.g. ide.sendActiveFile: false in settings.json, or a toggle in the extension UI) to disable this auto-attached context.

Current workaround: close the active tab before sending — disruptive when actively editing.

Environment:

• Claude Code VSCode extension
• macOS (Darwin 25.4.0)