Add timeout destination handling in call_flow_map

[eliweaver732]

What

This PR adds support for ring group timeout destination mapping in the call flow visualization. It enhances the build_ring_group() method in the call_flow_map.php class to detect and render exit actions (timeout handlers) for ring groups, including exit key information when available.

Why

Problem: The call flow map visualization was incomplete for ring groups. When a call failed to connect (timeout/no answer after retries), the system's exit action wasn't being visualized in the call flow diagram. This left operators and developers without visibility into where timeout calls would be routed.

Impact:

• For operators: Incomplete understanding of call routing logic for ring groups
• For developers: Harder to debug timeout routing issues or verify call flow configurations
• For compliance/documentation: Call flow diagrams couldn't accurately represent the full routing path

How It Works

The implementation adds a new code block in the build_ring_group() method that:

1. Extracts timeout destination data from the ring group record:

   • ring_group_timeout_app — the application/handler for timeout calls
   • ring_group_timeout_data — the destination data (e.g., phone number, extension)
   • ring_group_exit_key — optional key press (if defined) that triggers the exit

2. Creates a labeled node in the call flow:

   • Label defaults to "Exit"
   • If an exit key exists, appends it: "Exit / Key <key>"
   • This allows differentiation between timeout-triggered and key-press-triggered exits

3. Resolves the destination recursively using the existing resolve_destination() method, ensuring timeout destinations are fully mapped (e.g., if they route to another ring group, voicemail, or IVR).

Key Details

• Placement: Added after the "No Answer" forward destination handler, keeping related timeout/exit logic grouped together
• Null safety: Uses null coalescing operators (??) to safely handle missing fields
• Labeling: Smart label that includes exit key information for clarity
• Consistency: Uses the same resolve_destination() mechanism as other routing handlers, ensuring consistency across the call flow

Testing Recommendation

Verify this works with:

• Ring groups with timeout destinations configured
• Timeout destinations that chain to other applications (ring groups, IVRs, voicemail)