fix: resolve 2 dialyzer warnings for redundant nil guards on list values

Author: nyo16

lib/nous/agents/knowledge_base_agent.ex

@@ -85,7 +85,7 @@ defmodule Nous.Agents.KnowledgeBaseAgent do
     ctx = Context.add_message(ctx, response)
 
     # Track KB operations for reporting
-    tool_calls = response.tool_calls || []
+    tool_calls = response.tool_calls
 
     kb_calls =
       Enum.filter(tool_calls, fn call ->

lib/nous/knowledge_base/workflows.ex

@@ -261,7 +261,7 @@ defmodule Nous.KnowledgeBase.Workflows do
 
   defp build_health_report(state) do
     audit_output = state.data.audit_entries
-    issues = parse_json_output(audit_output) || []
+    issues = parse_json_output(audit_output)
     stats = state.data.stats
 
     report =