sl0ptty: M0 — libghostty-vt vendored, one pane, compositor, diff renderer

Design contract in DESIGN.md. libghostty-vt vendored fresh from ghostty
main@bedb6f2 (zig 0.16), built to a 14MB static lib.

M0: pty spawn (no libutil), a lib-vt terminal per pane, a screen cell buffer,
a diff emitter that repaints only what changed, raw mode, SIGWINCH, and a
~120Hz frame cap that coalesces pty reads.

Also the seed of the headless harness: --headless dumps the composited screen
without a tty, so composition is testable in milliseconds.

tests/live_m0.py covers what headless cannot: raw mode, the diff emitter,
resize propagation, and the quit path. 6/6 green.

1 files changed, 25 insertions, 0 deletions

diff --git a/vendor/libghostty-vt/src/os/mouse.zig b/vendor/libghostty-vt/src/os/mouse.zig
new file mode 100644
index 0000000..d68bb22
--- /dev/null
+++ b/vendor/libghostty-vt/src/os/mouse.zig
@@ -0,0 +1,25 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const objc = @import("objc");
+
+const log = std.log.scoped(.os);
+
+/// The system-configured double-click interval if its available.
+pub fn clickInterval() ?u32 {
+    return switch (builtin.os.tag) {
+        // On macOS, we can ask the system.
+        .macos => macos: {
+            const NSEvent = objc.getClass("NSEvent") orelse {
+                log.err("NSEvent class not found. Can't get click interval.", .{});
+                return null;
+            };
+
+            // Get the interval and convert to ms
+            const interval = NSEvent.msgSend(f64, objc.sel("doubleClickInterval"), .{});
+            const ms = @as(u32, @intFromFloat(@ceil(interval * 1000)));
+            break :macos ms;
+        },
+
+        else => null,
+    };
+}