Record /log whether or not anyone reads it, with the editor's messages in it

/log is now one ring (64 KiB, 4 KiB on the board) that records new, del,
rename and save, and a msg line for everything the editor says. An open
freezes it, so cat log shows what happened lately and ends; writing
follow to that same open makes reads past it wait for newer records, and
a follower the ring outran reads lost N first.

The message log keeps the pane's serial, not its reusable slot.

A test now fails when the tree serves a file /README never mentions; it
caught pty/status, now documented along with typing through pty/data.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/src/panes.zig b/src/panes.zig
index 0b4204aa..156d443a 100644
--- a/src/panes.zig
+++ b/src/panes.zig
@@ -3072,7 +3072,7 @@ pub const Output = struct {
         errdefer out.deinit();
         var i: usize = 0;
         while (p.messageLog(i)) |m| : (i += 1) {
-            if (m.pane != 0xff) try out.writer.print("{d}: ", .{m.pane});
+            if (m.serial != 0) try out.writer.print("{d}: ", .{m.serial});
             try out.writer.writeAll(m.slice());
             if (m.repeats > 1) try out.writer.print("  (x{d})", .{m.repeats});
             try out.writer.writeByte('\n');