feat: restore zhihu browser skills

Reconnect the recovered Zhihu skill flows to the live browser runtime and resolve their resources relative to the executable so they work outside the repo root.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/common/mod.rs

@@ -17,6 +17,7 @@ impl MockTransport {
         }
     }
 
+    #[allow(dead_code)]
     pub fn sent_messages(&self) -> Vec<AgentMessage> {
         self.sent.lock().unwrap().clone()
     }