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, 2 insertions, 0 deletions

diff --git a/src/memory.zig b/src/memory.zig
index b8a64a1a..7b6ee2c0 100644
--- a/src/memory.zig
+++ b/src/memory.zig
@@ -17,6 +17,8 @@ pub const limits = struct {
     pub const wrap_rows = if (board) 128 else 256;
     pub const undo_max = if (board) 16 else 256;
     pub const message_log = if (board) 16 else 128;
+    /// /log's ring, which records whether or not anyone reads it.
+    pub const log_bytes: usize = if (board) 4 * KiB else 64 * KiB;
     pub const max_tag_tail: usize = if (board) 512 else 4096;
     pub const host_path_cap: usize = if (board) 0 else 4095;
     /// -Dembed-sources: the editor serves its own sources under /src.