Unattended messages expire in the detached session's loop, not as a 9P request is served

serveFs expired them, but a read is answered while a step is out in a
syscall, because reads change nothing, and this one changed pane messages
and needs_frame from under the step. The detached session's loop now expires
them between steps, and while nobody is attached and a message is up it
looks again every 100 ms rather than waiting for something to wake it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/detached/server.zig b/src/detached/server.zig
index 6a4b5001..61fbe111 100644
--- a/src/detached/server.zig
+++ b/src/detached/server.zig
@@ -770,8 +770,10 @@ pub const Session = struct {
         const completed = s.ninep_wake.swap(false, .acq_rel) or drained;
         for (&s.clients) |*c| if (c.fd >= 0) s.flush(c);
         const regridded = s.reconcile();
-        // Nobody attached, nobody to dismiss a message (expireUnattended).
+        // Nobody attached, nobody to dismiss a message: the loop expires
+        // them itself, between the editor's steps (expireUnattended).
         s.core.unattended = s.primary() == null;
+        pardes.Messages.expireUnattended(s.core);
 
         const now = monotonicMs();
         var fds: [poll_slots]libc.pollfd = undefined;
@@ -904,6 +906,11 @@ pub const Session = struct {
                 due = if (due) |d| @min(d, at9) else at9;
             }
         }
+        // Unattended messages go on the clock: look again in a while.
+        if (s.core.unattended) for (s.core.panes) |slot| if (slot) |pane| if (pane.msg_len > 0) {
+            due = if (due) |d| @min(d, now + 100) else now + 100;
+            break;
+        };
         const at = due orelse return null;
         return @intCast(@max(0, @min(at - now, std.math.maxInt(c_int))));
     }