feat: implemented pruning conversation manager

Author: Ro-ee Tal

src/strands/agent/conversation_manager/__init__.py

@@ -8,13 +8,15 @@
   size while preserving conversation coherence
 - SummarizingConversationManager: An implementation that summarizes older context instead
   of simply trimming it
+- PruningConversationManager: An implementation that selectively prunes messages using configurable strategies
 
 Conversation managers help control memory usage and context length while maintaining relevant conversation state, which
 is critical for effective agent interactions.
 """
 
 from .conversation_manager import ConversationManager
 from .null_conversation_manager import NullConversationManager
+from .pruning_conversation_manager import PruningConversationManager
 from .sliding_window_conversation_manager import SlidingWindowConversationManager
 from .summarizing_conversation_manager import SummarizingConversationManager
 
@@ -23,4 +25,5 @@
     "NullConversationManager",
     "SlidingWindowConversationManager",
     "SummarizingConversationManager",
+    "PruningConversationManager",
 ]