Revert to Safari as default WebDriver browser

Chrome headless has too many issues:
- Session creation hangs when Chrome is already running
- Cloudflare and other bot protection blocks headless browsers
- Version mismatch issues between Chrome and ChromeDriver

Safari is more reliable for web automation on macOS.
Chrome headless is still available via --chrome-headless flag.

crates/g3-config/src/lib.rs

@@ -119,9 +119,9 @@ pub struct ComputerControlConfig {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Default)]
 #[serde(rename_all = "lowercase")]
 pub enum WebDriverBrowser {
+    #[default]
     Safari,
     #[serde(rename = "chrome-headless")]
-    #[default]
     ChromeHeadless,
 }
 
@@ -157,7 +157,7 @@ impl Default for WebDriverConfig {
             safari_port: 4444,
             chrome_port: 9515,
             chrome_binary: None,
-            browser: WebDriverBrowser::ChromeHeadless,
+            browser: WebDriverBrowser::Safari,
         }
     }
 }