feat(translators): improve system instruction extraction and input handling for OpenAI and Claude responses

- Enhanced support for extracting system instructions from input arrays.
- Improved input message role and type determination logic for consistent message processing.
- Refined instruction handling logic across translator types for better compatibility.

internal/runtime/executor/claude_executor.go

@@ -45,6 +45,7 @@ func (e *ClaudeExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, r
 	}
 	from := opts.SourceFormat
 	to := sdktranslator.FromString("claude")
+	// Use streaming translation to preserve function calling, except for claude.
 	body := sdktranslator.TranslateRequest(from, to, req.Model, bytes.Clone(req.Payload), from != to)
 
 	if !strings.HasPrefix(req.Model, "claude-3-5-haiku") {