Integrate with herdr cli.

src/Settings.zig

@@ -137,6 +137,16 @@ theme: Theme = .system,
 /// a mistyped chord and every shell in every tab exiting.
 confirm_quit: bool = true,
 
+/// Whether new terminals run in herdr-core (`hc`) rather than in a pty of the
+/// app's own.
+///
+/// Off by default: it needs `hc` installed, and it changes what quitting
+/// means. With it on, a shell's program belongs to the core, so closing the
+/// window — or the app crashing — leaves every shell and agent running, and
+/// the next launch restores the session without asking, attaching to them
+/// again. Closing a pane or a tab still ends what is in it. See `hc.zig`.
+herdr_core: bool = false,
+
 /// Whether a pane finishing posts a desktop notification.
 ///
 /// On by default. The whole shape of this app is "set something going in a tab
@@ -268,6 +278,10 @@ fn parse(self: *Settings, text: []const u8) ParseError!void {
         if (value == .bool) self.confirm_quit = value.bool;
     }
 
+    if (root.get("herdr_core")) |value| {
+        if (value == .bool) self.herdr_core = value.bool;
+    }
+
     if (root.get("notifications")) |value| {
         if (value == .bool) self.notifications = value.bool;
     }
@@ -623,6 +637,8 @@ fn serialize(self: *Settings) SaveError![]u8 {
     try json.write(@tagName(self.theme));
     try json.objectField("confirm_quit");
     try json.write(self.confirm_quit);
+    try json.objectField("herdr_core");
+    try json.write(self.herdr_core);
     try json.objectField("notifications");
     try json.write(self.notifications);