Clean up tool output formatting

- Shell: "✅ Command executed successfully" → "⚡️ ran successfully"
- Write file: Remove ✏️ emoji, use plain "wrote N lines | M chars"

crates/g3-core/src/tools/file_ops.rs

@@ -343,7 +343,7 @@ pub async fn execute_write_file<W: UiWriter>(
                     format!("{}", char_count)
                 };
                 Ok(format!(
-                    "✅ wrote {} lines | {} chars",
+                    "wrote {} lines | {} chars",
                     line_count, char_display
                 ))
             }