A desktop session holds 64 panes, and every route that finds none free says so

Sixteen panes was far too few for a real session. MAX_PANES is now 64 on a
desktop and stays 16 on the board; the 48 more slots cost about 3.7 KB each
in fixed tables (the core 1.33 to 1.45 MB, its surface 19 to 72 KB), and a
pane itself (84 KB and its terminal) is allocated only when it opens. At the
cap, pane/new fails with `pane/new: no pane slots: 64 max` and an err
record rather than a bare ENFILE, a 9P look or exec that would open a pane
fails its write with the same words and reads back empty, and New, Tty,
Tutor and Alt-n say it on the message row (their ctl writes fail with it).

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

1 files changed, 2 insertions, 2 deletions

diff --git a/src/exec.zig b/src/exec.zig
index 2f279d8e..d4480e00 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -312,7 +312,7 @@ pub fn spawnV9fsTty(p: *Pardes, from: usize) void {
 fn spawnTtyWithMount(p: *Pardes, from: usize, v9fs: bool) ?*Pane {
     const src = p.panes[from] orelse return null;
     const free = p.freeSlot() orelse {
-        p.reportFailure(from, "Tty: no pane free");
+        p.reportError(from, "Tty", error.NoPaneSlots);
         return null;
     };
     const nt = p.newShell(free, Pardes.paneDir(src)) catch |err| {
@@ -609,7 +609,7 @@ fn runCommand(p: *Pardes, from: usize, line: []const u8) ?usize {
         return id;
     }
     const free = p.freeSlot() orelse {
-        p.reportFailure(from, "exec: no pane free for the command");
+        p.reportError(from, "exec", error.NoPaneSlots);
         return null;
     };
     const pane = p.newCommand(free, dir, line) catch |err| {