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, 0 deletions

diff --git a/test/panes.zig b/test/panes.zig
index 2d3aed43..2f307cb5 100644
--- a/test/panes.zig
+++ b/test/panes.zig
@@ -2193,6 +2193,7 @@ test "document panes ignore terminal output without allocating terminal state" {
     const p = try Pardes.init(allocator.allocator(), .{ .tty_only = true });
     defer p.deinit();
     const pane = try p.setTestFile("document body\n");
+    p.update(.tick); // the step that installed it records it in /log
     while (p.nextEffect()) |_| {}
     const revision = pane.file.?.revision;
     const allocations = allocator.alloc_index;