Add ability to pick multi service bodies

[californiasteve]

Add ability to select multiple entries from the service body select for events that are being held by multiple ASCs, Regions or Zones.

[dgershman]

Multi-Service Body Selection Implemented ✅

I've successfully implemented the ability to select multiple service bodies when submitting events. Here's what's been added:

🌟 New Features

• Multi-Select Interface: Service body selection now uses checkboxes instead of a single dropdown
• Multiple Selection Support: Users can select one or more ASCs, Regions, or Zones for events
• Clear Labeling: Interface shows "(Select one or more)" to guide users
• Validation: Form ensures at least one service body is selected before submission

🔧 Technical Implementation

• Frontend: Changed from single select dropdown to checkbox list (similar to categories/tags)
• Backend: Already supported multiple service bodies via comma-separated values
• Admin Display: Updated admin event list to show multiple service bodies properly
• Data Storage: Service bodies stored as comma-separated values (e.g., "123,456,789")
• Backward Compatibility: Existing single service body events continue to work

💡 User Experience

Before: Users could only select one service body per event
After: Users can select multiple service bodies for joint events

Example Use Cases:

• Multi-region conventions
• Joint ASC activities
• Zone-wide service events
• Inter-area collaborations

📋 Form Interface

The service body selection now appears as a checkbox list with all available service bodies:

• ☐ Metro ASC (123)
• ☐ Valley Region (456)
• ☐ Mountain Zone (789)
• ☐ Unaffiliated (0)

🔄 Filtering & Display

• Event Lists: Continue to work with multi-service body filtering
• RSS Feeds: Support multiple service body parameters
• Admin Area: Shows all selected service bodies in event listings
• Search: Events appear when filtering by any of their assigned service bodies

The implementation maintains full backward compatibility while enabling the requested multi-service body functionality for joint events and collaborations.

Status: Ready for testing and use! 🚀

[californiasteve]

Awesome job Danny