Help Bubbles: Wire notification system to UI

[malpern]

Problem

Help bubble callback logs messages but isn't connected to actual UI notification system.

Location

RuntimeCoordinator.swift lines 1089-1092

AppLogger.shared.log(
    "ℹ️ [Bubble] Help bubble would be shown here (needs notification-based implementation)")

Impact

Callback infrastructure exists but users don't see help bubbles.

Fix

1. Connect callback to actual notification UI
2. Implement bubble display logic
3. Test bubble appearance

References

• Comprehensive review: docs/code-review/comprehensive-feature-review.md section 6.3