matrix: setup livekit

Needed for element X calls.

services/livekit.nix

@@ -0,0 +1,53 @@
+{
+  service_configs,
+  ...
+}:
+let
+  keyFile = ../secrets/livekit_keys;
+
+  ports = service_configs.ports;
+in
+{
+  services.livekit = {
+    enable = true;
+    inherit keyFile;
+    openFirewall = true;
+
+    settings = {
+      port = ports.livekit;
+      bind_addresses = [ "127.0.0.1" ];
+
+      rtc = {
+        port_range_start = 50100;
+        port_range_end = 50200;
+        use_external_ip = true;
+      };
+
+      # Disable LiveKit's built-in TURN; coturn is already running
+      turn = {
+        enabled = false;
+      };
+
+      logging = {
+        level = "info";
+      };
+    };
+  };
+
+  services.lk-jwt-service = {
+    enable = true;
+    inherit keyFile;
+    livekitUrl = "wss://${service_configs.livekit.domain}";
+    port = ports.lk_jwt;
+  };
+
+  services.caddy.virtualHosts."${service_configs.livekit.domain}".extraConfig = ''
+    @jwt path /sfu/get /healthz
+    handle @jwt {
+      reverse_proxy :${builtins.toString ports.lk_jwt}
+    }
+    handle {
+      reverse_proxy :${builtins.toString ports.livekit}
+    }
+  '';
+}