feat: Add DNS timings and resolution overrides (#360)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

crates/yaak-http/src/manager.rs

@@ -1,4 +1,5 @@
 use crate::client::HttpConnectionOptions;
+use crate::dns::LocalhostResolver;
 use crate::error::Result;
 use log::info;
 use reqwest::Client;
@@ -7,8 +8,15 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 use tokio::sync::RwLock;
 
+/// A cached HTTP client along with its DNS resolver.
+/// The resolver is needed to set the event sender per-request.
+pub struct CachedClient {
+    pub client: Client,
+    pub resolver: Arc<LocalhostResolver>,
+}
+
 pub struct HttpConnectionManager {
-    connections: Arc<RwLock<BTreeMap<String, (Client, Instant)>>>,
+    connections: Arc<RwLock<BTreeMap<String, (CachedClient, Instant)>>>,
     ttl: Duration,
 }
 
@@ -20,21 +28,26 @@ impl HttpConnectionManager {
         }
     }
 
-    pub async fn get_client(&self, opt: &HttpConnectionOptions) -> Result<Client> {
+    pub async fn get_client(&self, opt: &HttpConnectionOptions) -> Result<CachedClient> {
         let mut connections = self.connections.write().await;
         let id = opt.id.clone();
 
         // Clean old connections
         connections.retain(|_, (_, last_used)| last_used.elapsed() <= self.ttl);
 
-        if let Some((c, last_used)) = connections.get_mut(&id) {
+        if let Some((cached, last_used)) = connections.get_mut(&id) {
             info!("Re-using HTTP client {id}");
             *last_used = Instant::now();
-            return Ok(c.clone());
+            return Ok(CachedClient {
+                client: cached.client.clone(),
+                resolver: cached.resolver.clone(),
+            });
         }
 
-        let c = opt.build_client()?;
-        connections.insert(id.into(), (c.clone(), Instant::now()));
-        Ok(c)
+        let (client, resolver) = opt.build_client()?;
+        let cached = CachedClient { client: client.clone(), resolver: resolver.clone() };
+        connections.insert(id.into(), (cached, Instant::now()));
+
+        Ok(CachedClient { client, resolver })
     }
 }