Break juri apart and add scaffolding for system timers

hosts/juri/bskyannouncements.nix

@@ -0,0 +1,23 @@
+{ pkgs, ... }:
+{
+  systemd.timers."bsky-announcements" = {
+    wantedBy = [ "timers.target" ];
+    timerConfig = {
+      OnBootSec = "20s";
+      # OnCalendar = "Thu *-*-* 8:00:00 America/Los_Angeles";
+      # Persistent = true;
+      Unit = "bsky-announcements.service";
+    };
+  };
+
+  systemd.services."bsky-announcements" = {
+    script = ''
+      set -eu
+      ${pkgs.coreutils}/bin/echo "Hello World"
+    '';
+    serviceConfig = {
+      Type = "oneshot";
+      User = "root";
+    };
+  };
+}