[FEATURE] Native IDE notifications for Claude Code plugins (VS Code, JetBrains, Xcode)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Context

This is a follow-up to #6091 (34 upvotes, closed due to inactivity, now locked). The need is still present and unaddressed.

Problem

When Claude Code is running inside an IDE plugin, there is no native notification when:

• A task completes
• Claude is waiting for user input
• An error occurs

Users working in other files or tabs have no way to know Claude Code needs attention without manually checking the panel.

Proposed Solution

Expose Claude Code lifecycle events (task complete, awaiting input, error) to each IDE's native notification system:

• VS Code — window.showInformationMessage / showWarningMessage / showErrorMessage
• JetBrains — Notifications API (integrates with OS-level notifications)
• Xcode — UserNotifications framework or Xcode Source Editor Extension messaging

Each IDE already handles system-level notification routing (macOS, Windows, Linux), so users would get consistent behavior with their existing OS notification preferences.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Developer tools/SDK

Use Case Example

• Long-running generation finishes while user is in another file or application
• Claude Code pauses for input and the user doesn't notice
• An error occurs silently in a background tab

Additional Context

• #30672 suggests some notification behavior already exists on macOS (terminal CLI), but it is not integrated into IDE plugins
• Xcode support would be especially valuable as the plugin matures