Add developer message support to realtime adapters

OpenAI Realtime, Grok Realtime, and AWS Nova Sonic adapters now convert
"developer" role messages to "user" (consistent with all other non-OpenAI
adapters). Previously these messages were silently dropped. Adds starter
unit tests for all three realtime adapters.

src/pipecat/adapters/services/aws_nova_sonic_adapter.py

@@ -125,7 +125,8 @@ class AWSNovaSonicLLMAdapter(BaseLLMAdapter[AWSNovaSonicLLMInvocationParams]):
 
         universal_context_messages = copy.deepcopy(universal_context_messages)
 
-        # If we have a "system" message as our first message, let's pull that out into "instruction"
+        # If we have a "system" message as our first message,
+        # pull that out into "instruction"
         if universal_context_messages[0].get("role") == "system":
             system = universal_context_messages.pop(0)
             content = system.get("content")
@@ -136,8 +137,13 @@ class AWSNovaSonicLLMAdapter(BaseLLMAdapter[AWSNovaSonicLLMInvocationParams]):
             if system_instruction:
                 self._system_instruction = system_instruction
 
+        # Convert any remaining "system"/"developer" messages to "user",
+        # as Nova Sonic only supports "user" and "assistant" in history.
+        for msg in universal_context_messages:
+            if msg.get("role") in ("system", "developer"):
+                msg["role"] = "user"
+
         # Process remaining messages to fill out conversation history.
-        # Nova Sonic supports "user" and "assistant" messages in history.
         for universal_context_message in universal_context_messages:
             message = self._from_universal_context_message(universal_context_message)
             if message:

src/pipecat/adapters/services/grok_realtime_adapter.py

@@ -128,6 +128,11 @@ class GrokRealtimeLLMAdapter(BaseLLMAdapter):
             if not messages:
                 return self.ConvertedMessages(messages=[], system_instruction=system_instruction)
 
+        # Convert any remaining "system"/"developer" messages to "user"
+        for msg in messages:
+            if msg.get("role") in ("system", "developer"):
+                msg["role"] = "user"
+
         # Single user message can be sent normally
         if len(messages) == 1 and messages[0].get("role") == "user":
             return self.ConvertedMessages(

src/pipecat/adapters/services/open_ai_realtime_adapter.py

@@ -116,8 +116,8 @@ class OpenAIRealtimeLLMAdapter(BaseLLMAdapter):
         messages = copy.deepcopy(universal_context_messages)
         system_instruction = None
 
-        # If we have a "system" message as our first message, let's pull that out into session
-        # "instructions"
+        # If we have a "system" message as our first message,
+        # pull that out into session "instructions"
         if messages[0].get("role") == "system":
             system = messages.pop(0)
             content = system.get("content")
@@ -128,6 +128,11 @@ class OpenAIRealtimeLLMAdapter(BaseLLMAdapter):
             if not messages:
                 return self.ConvertedMessages(messages=[], system_instruction=system_instruction)
 
+        # Convert any remaining "system"/"developer" messages to "user"
+        for msg in messages:
+            if msg.get("role") in ("system", "developer"):
+                msg["role"] = "user"
+
         # If we have just a single "user" item, we can just send it normally
         if len(messages) == 1 and messages[0].get("role") == "user":
             return self.ConvertedMessages(