feat: add tool execution support with sandboxed environment and validation

Implement EventHandler class for streaming tool call processing, add demo_tools console script and Makefile target, introduce demo_tools.py with echo and remember functions, and update ReplikaAgent with temperature parameter in demo_replika.py

Makefile

@@ -1,6 +1,7 @@
 DEMO_REPLIKA = .venv/bin/ragent.demo_replika 
 DEMO_DISCUSS = .venv/bin/ragent.demo_discuss 
 DEMO_BATCH_MESSAGES = .venv/bin/ragent.demo_batch_messages
+DEMO_TOOLS = .venv/bin/ragent.demo_tools
 PIP = .venv/bin/pip 
 
 default:
@@ -24,3 +25,7 @@ demo_discuss:
 demo_batch_messages:
 	@echo "Executing Batch Messages Demo."
 	$(DEMO_BATCH_MESSAGES)
+
+demo_tools:
+	@echo "Executing Tools Demo."
+	$(DEMO_TOOLS)