feat: add hyprscratch scratchpad management with rule reapply fork

- Add hyprscratch from colonelpanic8/reapply-rules-on-toggle fork that
  reapplies size/position/float rules on every toggle (not just spawn)
- Configure 9 scratchpads: htop, volume, spotify, element, slack,
  transmission, dropdown, gmail, messages
- Use clean mode (hide on workspace change) and auto-dismiss (only
  dropdown persists)
- Fix pavucontrol class (org.pulseaudio.pavucontrol) and dropdown
  position (offset by taffybar height)
- Add kanshi-sni, dbus-menu, dbus-hslogger flake inputs and follows

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

nixos/flake.nix

@@ -55,6 +55,14 @@
       };
     };
 
+    kanshi-sni = {
+      url = "github:taffybar/kanshi-sni";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
+
     # Hyprland and plugins from official flakes for proper plugin compatibility
     hyprland = {
       url = "git+https://github.com/hyprwm/Hyprland?submodules=1&ref=refs/tags/v0.53.0";
@@ -70,6 +78,11 @@
       inputs.hyprland.follows = "hyprland";
     };
 
+    hyprscratch = {
+      url = "github:colonelpanic8/hyprscratch/reapply-rules-on-toggle";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     railbird-secrets = {
       url = "git+ssh://gitea@dev.railbird.ai:1123/railbird/secrets-flake.git";
       inputs = {
@@ -112,6 +125,8 @@
         status-notifier-item.follows = "status-notifier-item";
         xmonad.follows = "xmonad";
         xmonad-contrib.follows = "xmonad-contrib";
+        dbus-menu.follows = "dbus-menu";
+        dbus-hslogger.follows = "dbus-hslogger";
         weeder-nix.inputs.pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
       };
     };
@@ -123,6 +138,11 @@
         flake-utils.follows = "flake-utils";
         xmonad.follows = "xmonad";
         taffybar.follows = "taffybar";
+        dbus-menu.follows = "dbus-menu";
+        dbus-hslogger.follows = "dbus-hslogger";
+        gtk-sni-tray.follows = "gtk-sni-tray";
+        gtk-strut.follows = "gtk-strut";
+        status-notifier-item.follows = "status-notifier-item";
       };
     };
 
@@ -142,6 +162,8 @@
         flake-utils.follows = "flake-utils";
         git-ignore-nix.follows = "git-ignore-nix";
         status-notifier-item.follows = "status-notifier-item";
+        gtk-strut.follows = "gtk-strut";
+        dbus-menu.follows = "dbus-menu";
       };
     };
 
@@ -163,6 +185,20 @@
       };
     };
 
+    dbus-menu = {
+      url = "github:taffybar/dbus-menu";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+        git-ignore-nix.follows = "git-ignore-nix";
+      };
+    };
+
+    dbus-hslogger = {
+      url = "github:IvanMalison/dbus-hslogger";
+      flake = false;
+    };
+
     vscode-server = {
       url = "github:nix-community/nixos-vscode-server";
       inputs = {