feat: mcp router extension discovery and install tool (#1995)

Co-authored-by: Alice Hau <ahau@squareup.com>

crates/goose/src/config/extensions.rs

@@ -63,6 +63,22 @@ impl ExtensionManager {
         }))
     }
 
+    pub fn get_config_by_name(name: &str) -> Result<Option<ExtensionConfig>> {
+        let config = Config::global();
+
+        // Try to get the extension entry
+        let extensions: HashMap<String, ExtensionEntry> = match config.get_param("extensions") {
+            Ok(exts) => exts,
+            Err(super::ConfigError::NotFound(_)) => HashMap::new(),
+            Err(_) => HashMap::new(),
+        };
+
+        Ok(extensions
+            .values()
+            .find(|entry| entry.config.name() == name)
+            .map(|entry| entry.config.clone()))
+    }
+
     /// Set or update an extension configuration
     pub fn set(entry: ExtensionEntry) -> Result<()> {
         let config = Config::global();