Add generic session panel stack

src/main.zig

@@ -3,6 +3,7 @@ const input = @import("input.zig");
 const layout = @import("layout.zig");
 const leader = @import("leader.zig");
 const mobile_acceptance = @import("mobile_acceptance.zig");
+const panel = @import("panel.zig");
 const protocol = @import("protocol.zig");
 const replay = @import("replay.zig");
 const session = @import("session.zig");
@@ -125,6 +126,7 @@ test {
     _ = layout;
     _ = leader;
     _ = mobile_acceptance;
+    _ = panel;
     _ = protocol;
     _ = replay;
     _ = session;