fix(anthropic): skip tool calls with empty names to prevent API errors

When building parameters for Anthropic API calls, tool calls with empty
names would cause 400 Bad Request errors with the message:
'tool_use.name: String should have at least 1 character'

This fix adds a check to skip tool calls that have empty names, preventing
the API error and allowing the conversation to continue normally.

Fixes #1658

pkg/providers/anthropic/provider.go

@@ -180,6 +180,10 @@ func buildParams(
 					blocks = append(blocks, anthropic.NewTextBlock(msg.Content))
 				}
 				for _, tc := range msg.ToolCalls {
+					// Skip tool calls with empty names to avoid API errors
+					if tc.Name == "" {
+						continue
+					}
 					args := tc.Arguments
 					if args == nil && tc.Function != nil && tc.Function.Arguments != "" {
 						if err := json.Unmarshal([]byte(tc.Function.Arguments), &args); err != nil {