feat: v3.4.0 — OpenPanel plugin public release (42 tools)

OpenPanel product analytics plugin fully reviewed, tested, and published.
Works with both self-hosted and cloud (openpanel.dev) instances.

- 42 tools: event tracking, data export, analytics, project/client management
- All tools use public REST APIs (Track, Export, Insights, Manage)
- Client modes: write (tracking), read (analytics), root (full access)
- Service page with description, setup notes, WordPress plugin download
- Dynamic URL hints in Add Site form
- 62 unit tests
- ENABLED_PLUGINS default now includes openpanel

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_admin_system.py

@@ -1,5 +1,6 @@
 """Tests for Admin System Unification (F.4)."""
 
+
 from core.dashboard.auth import (
     DashboardSession,
     get_session_display_info,