picom: fix animations config syntax for libconfig

Home-manager generates [] (arrays) but picom needs () (lists) for
the animations setting. Move animations to a separate config file
with correct syntax and override the picom service to load both.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nixos/xmonad.nix

@@ -98,68 +98,8 @@ makeEnable config "myModules.xmonad" true  {
       backend = "glx";
 
       settings = {
-        # Spring physics animations (mainline picom with spring-physics branch)
+        # Note: animations must use () not [] in libconfig, so we put them in extraArgs
-        # Syntax: spring(stiffness, dampening, mass) or spring(stiffness, dampening, mass, clamping)
+        # via xdg.configFile below
-        # Set clamping to false for bounce/overshoot effects
-        animations = [
-          # Window move/resize animation with spring physics
-          {
-            triggers = ["geometry"];
-            offset-x = {
-              curve = "spring(250, 20, 1, false)";
-              start = "window-x-before - window-x";
-              end = 0;
-            };
-            offset-y = {
-              curve = "spring(250, 20, 1, false)";
-              start = "window-y-before - window-y";
-              end = 0;
-            };
-          }
-          # Opacity fade animation
-          {
-            triggers = ["open" "show"];
-            opacity = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = 0;
-              end = "window-raw-opacity";
-            };
-            scale-x = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = 0.9;
-              end = 1;
-            };
-            scale-y = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = 0.9;
-              end = 1;
-            };
-          }
-          {
-            triggers = ["close" "hide"];
-            opacity = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = "window-raw-opacity";
-              end = 0;
-            };
-            scale-x = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = 1;
-              end = 0.9;
-            };
-            scale-y = {
-              curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
-              duration = 0.2;
-              start = 1;
-              end = 0.9;
-            };
-          }
-        ];
 
         fade-in-step = 0.028;
         fade-out-step = 0.028;
@@ -198,6 +138,78 @@ makeEnable config "myModules.xmonad" true  {
       };
     };
 
+    # Spring physics animations config - written separately because home-manager
+    # generates [] (arrays) but picom needs () (lists) for animations
+    xdg.configFile."picom/animations.conf".text = ''
+      # Spring physics animations (mainline picom with spring-physics branch)
+      # Syntax: spring(stiffness, dampening, mass) or spring(stiffness, dampening, mass, clamping)
+      # Set clamping to false for bounce/overshoot effects
+      animations = (
+        # Window move/resize animation with spring physics
+        {
+          triggers = ["geometry"];
+          offset-x = {
+            curve = "spring(250, 20, 1, false)";
+            start = "window-x-before - window-x";
+            end = 0;
+          };
+          offset-y = {
+            curve = "spring(250, 20, 1, false)";
+            start = "window-y-before - window-y";
+            end = 0;
+          };
+        },
+        # Opacity fade animation
+        {
+          triggers = ["open", "show"];
+          opacity = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = 0;
+            end = "window-raw-opacity";
+          };
+          scale-x = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = 0.9;
+            end = 1;
+          };
+          scale-y = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = 0.9;
+            end = 1;
+          };
+        },
+        {
+          triggers = ["close", "hide"];
+          opacity = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = "window-raw-opacity";
+            end = 0;
+          };
+          scale-x = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = 1;
+            end = 0.9;
+          };
+          scale-y = {
+            curve = "cubic-bezier(0.25, 0.1, 0.25, 1)";
+            duration = 0.2;
+            start = 1;
+            end = 0.9;
+          };
+        }
+      );
+    '';
+
+    # Override picom service to include animations config
+    systemd.user.services.picom = {
+      Service.ExecStart = pkgs.lib.mkForce "${pkgs.picom}/bin/picom --config \${XDG_CONFIG_HOME}/picom/picom.conf --config \${XDG_CONFIG_HOME}/picom/animations.conf";
+    };
+
     # systemd.user.services.notifications-tray-icon = {
     #   Unit = {
     #     Description = "Notifications tray icon";