CI concurrency + deep-merge config fragments; fix clawdinator-2 channels

- Cancel in-progress image builds on new pushes (concurrency)
- Add services.clawdinator.configFragments for deep-merge tweaks
- Use configFragments in clawdinator-2 to disable telegram without clobbering discord

No host changes; intended to ship via next AMI build.

.github/workflows/image-build.yml

@@ -1,5 +1,9 @@
 name: Build NixOS Image
 
+concurrency:
+  group: image-build-${{ github.ref }}
+  cancel-in-progress: true
+
 on:
   workflow_dispatch:
   push:

nix/hosts/clawdinator-2.nix

@@ -21,6 +21,10 @@
 
   networking.firewall.allowedTCPPorts = [ 22 ];
 
-  services.clawdinator.config.plugins.entries.telegram.enabled = false;
-  services.clawdinator.config.channels.telegram.enabled = false;
+  services.clawdinator.configFragments = [
+    {
+      plugins.entries.telegram.enabled = false;
+      channels.telegram.enabled = false;
+    }
+  ];
 }

nix/modules/clawdinator.nix

@@ -2,10 +2,13 @@
 let
   cfg = config.services.clawdinator;
 
+  configFragmentsMerged = lib.foldl' lib.recursiveUpdate {} cfg.configFragments;
+  effectiveConfig = lib.recursiveUpdate cfg.config configFragmentsMerged;
+
   configSource =
     if cfg.configFile != null
     then cfg.configFile
-    else pkgs.writeText "openclaw.json" (builtins.toJSON cfg.config);
+    else pkgs.writeText "openclaw.json" (builtins.toJSON effectiveConfig);
 
   updateScript = pkgs.writeShellScript "clawdinator-self-update" ''
     set -euo pipefail
@@ -310,7 +313,13 @@ in
     config = mkOption {
       type = types.attrs;
       default = {};
-      description = "Raw Clawbot config JSON (merged into openclaw.json).";
+      description = "Raw Clawbot config JSON (base).";
+    };
+
+    configFragments = mkOption {
+      type = types.listOf types.attrs;
+      default = [];
+      description = "Additional OpenClaw config fragments, recursively merged into services.clawdinator.config (deep merge). Use this for small per-host tweaks without clobbering sibling keys.";
     };
 
     configFile = mkOption {