UI writer abstraction instead of printlns everywhere

crates/g3-cli/src/ui_writer_impl.rs

@@ -0,0 +1,81 @@
+use g3_core::ui_writer::UiWriter;
+use std::io::{self, Write};
+
+/// Console implementation of UiWriter that prints to stdout
+pub struct ConsoleUiWriter;
+
+impl ConsoleUiWriter {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl UiWriter for ConsoleUiWriter {
+    fn print(&self, message: &str) {
+        println!("{}", message);
+    }
+    
+    fn println(&self, message: &str) {
+        println!("{}", message);
+    }
+    
+    fn print_inline(&self, message: &str) {
+        print!("{}", message);
+        let _ = io::stdout().flush();
+    }
+    
+    fn print_system_prompt(&self, prompt: &str) {
+        println!("🔍 System Prompt:");
+        println!("================");
+        println!("{}", prompt);
+        println!("================");
+        println!();
+    }
+    
+    fn print_context_status(&self, message: &str) {
+        println!("{}", message);
+    }
+    
+    fn print_tool_header(&self, tool_name: &str) {
+        println!("┌─ {}", tool_name);
+    }
+    
+    fn print_tool_arg(&self, key: &str, value: &str) {
+        println!("│ {}: {}", key, value);
+    }
+    
+    fn print_tool_output_header(&self) {
+        println!("├─ output:");
+    }
+    
+    fn print_tool_output_line(&self, line: &str) {
+        println!("│ {}", line);
+    }
+    
+    fn print_tool_output_summary(&self, hidden_count: usize) {
+        println!(
+            "│ ... ({} more line{} hidden)",
+            hidden_count,
+            if hidden_count == 1 { "" } else { "s" }
+        );
+    }
+    
+    fn print_tool_timing(&self, duration_str: &str) {
+        println!("└─ ⚡️ {}", duration_str);
+        println!();
+    }
+    
+    fn print_agent_prompt(&self) {
+        print!("🤖 ");
+        let _ = io::stdout().flush();
+    }
+    
+    fn print_agent_response(&self, content: &str) {
+        print!("{}", content);
+        let _ = io::stdout().flush();
+    }
+    
+    fn flush(&self) {
+        let _ = io::stdout().flush();
+    }
+}