arr-interconnect: add gawk to PATH for idempotency check

The quality-floor helper uses awk to compare floats (since jq output
can be 10 vs 10.0 depending on type). Without gawk on PATH, the check
failed silently and every run issued PUTs even when values already
matched.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

services/arr-interconnect.nix

@@ -2,7 +2,7 @@
 let
   interconnectScript = pkgs.writeShellScript "arr-interconnect" ''
     set -euo pipefail
-    PATH="${lib.makeBinPath [ pkgs.curl pkgs.jq pkgs.gnused pkgs.gnugrep pkgs.coreutils ]}:$PATH"
+    PATH="${lib.makeBinPath [ pkgs.curl pkgs.jq pkgs.gnused pkgs.gnugrep pkgs.gawk pkgs.coreutils ]}:$PATH"
 
     BASE="http://127.0.0.1"