fix: refresh the session before the access token expires

jacquard 0.12.2 only refreshes on a 401, but the PDS reports expiry as a 400
ExpiredToken, so DM polling failed after about two hours.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/dms.rs

@@ -1,4 +1,4 @@
-use std::time::Duration;
+use std::time::{Duration, Instant};
 
 use anyhow::Result;
 use jacquard::api::app_bsky::graph::get_relationships::{
@@ -19,6 +19,9 @@ use crate::cities::Cities;
 use crate::labeler::Labeler;
 
 const POLL_INTERVAL: Duration = Duration::from_secs(3);
+// Access tokens last about two hours. jacquard 0.12.2 only refreshes after a
+// 401, but the PDS reports expiry as a 400 `ExpiredToken`, so refresh ahead of it.
+const REFRESH_INTERVAL: Duration = Duration::from_secs(30 * 60);
 const CURSOR_KEY: &str = "chat_cursor";
 const CHAT_SERVICE: &str = "did:web:api.bsky.chat#bsky_chat";
 
@@ -46,7 +49,14 @@ fn chat() -> CallOptions {
 
 impl Dms<'_> {
     pub async fn run(&self) {
+        let mut last_refresh = Instant::now();
         loop {
+            if last_refresh.elapsed() >= REFRESH_INTERVAL {
+                match self.agent.refresh().await {
+                    Ok(_) => last_refresh = Instant::now(),
+                    Err(err) => eprintln!("session refresh failed: {err:#}"),
+                }
+            }
             if let Err(err) = self.poll().await {
                 eprintln!("chat poll failed: {err:#}");
             }