dashboard: same bind retry policy as the agent half

dashboard.rs had the same 12-attempt cap shape as the per-agent
bind_with_retry. Apply the same fix — retry forever with the 2s-capped
backoff, WARN early then INFO once we're clearly stuck on a stale
socket, INFO on success when we did have to retry. Mirrors the
agent change in this PR.

hive-c0re/src/dashboard.rs

@@ -84,19 +84,43 @@ pub async fn serve(port: u16, coord: Arc<Coordinator>) -> Result<()> {
 // `/dashboard/stream` for the unified live event channel.
 // ---------------------------------------------------------------------------
 
-/// `SO_REUSEADDR` bind with retry. Mirrors the per-agent variant —
+/// `SO_REUSEADDR` bind with retry. Mirrors the per-agent variant in
-/// hive-c0re restarts also race the previous process's socket release.
+/// `hive-ag3nt::web_ui::bind_with_retry`: hive-c0re restarts also
+/// race the previous process's socket release, and the retry has no
+/// attempt cap — capping was the proximate cause of issue #324
+/// (silent give-up on a long stale socket). Genuine port collisions
+/// don't reach this layer (dashboard is bound to a fixed configured
+/// port, no per-agent hashing), so any persistent `AddrInUse` always
+/// reflects a recoverable stale socket. WARN for the first dozen
+/// attempts; INFO after that to avoid spamming the journal during a
+/// long hold; INFO on eventual success when we did have to retry.
 async fn bind_with_retry(addr: SocketAddr) -> Result<tokio::net::TcpListener> {
     let mut delay_ms = 250u64;
     let mut attempts = 0u32;
     loop {
         match try_bind(addr) {
-            Ok(l) => return Ok(l),
+            Ok(l) => {
-            Err(e) if e.kind() == std::io::ErrorKind::AddrInUse && attempts < 12 => {
+                if attempts > 0 {
+                    tracing::info!(
+                        %addr, attempts,
+                        "dashboard: bind succeeded after retry"
+                    );
+                }
+                return Ok(l);
+            }
+            Err(e) if e.kind() == std::io::ErrorKind::AddrInUse => {
+                let attempt = attempts + 1;
+                if attempt <= 12 {
                     tracing::warn!(
-                    %addr, attempt = attempts + 1,
+                        %addr, attempt,
                         "dashboard: AddrInUse, retrying in {delay_ms}ms"
                     );
+                } else {
+                    tracing::info!(
+                        %addr, attempt,
+                        "dashboard: AddrInUse still holding, retrying in {delay_ms}ms"
+                    );
+                }
                 tokio::time::sleep(std::time::Duration::from_millis(delay_ms)).await;
                 attempts += 1;
                 delay_ms = (delay_ms * 2).min(2000);