Refactor AIEngine and registry to improve function ID generation and support legacy names

- Updated AIEngine to normalize function names by replacing underscores with hyphens in generated function IDs for better consistency with frontend tracking.
- Enhanced registry to resolve function name aliases, allowing for backward compatibility with legacy function names when retrieving function instances.

backend/igny8_core/ai/engine.py

@@ -83,7 +83,9 @@ class AIEngine:
             function_name = fn.get_name()
             
             # Generate function_id for tracking (ai-{function_name}-01)
-            function_id = f"ai-{function_name}-01"
+            # Normalize underscores to hyphens to match frontend tracking IDs
+            function_id_base = function_name.replace('_', '-')
+            function_id = f"ai-{function_id_base}-01"
             
             # Get model config from settings (Stage 4 requirement)
             model_config = get_model_config(function_name)

backend/igny8_core/ai/registry.py

@@ -54,7 +54,15 @@ def list_functions() -> list:
 
 def get_function_instance(name: str) -> Optional[BaseAIFunction]:
     """Get function instance by name - lazy loads if needed"""
-    fn_class = get_function(name)
+    # Resolve alias first to support legacy function names
+    try:
+        from igny8_core.ai.settings import FUNCTION_ALIASES
+    except ImportError:
+        FUNCTION_ALIASES = {}
+    
+    actual_name = FUNCTION_ALIASES.get(name, name)
+    
+    fn_class = get_function(actual_name)
     if fn_class:
         return fn_class()
     return None