Enhance 14900k configuration with streaming display support and virtual EDID generation

- Added a new `streaming-display.nix` module to configure a headless 4K virtual output for Sunshine and Moonlight.
- Introduced a Python script `generate-virtual-edid.py` to create a virtual display EDID with 4K capabilities.
- Updated `configuration.nix` to integrate the new streaming display module and enable related services.
- Modified `displays.nix` to accommodate the new streaming display settings and ensure compatibility with existing GPU passthrough configurations.

modules/hosts/14900k/_private/displays.nix

@@ -1,5 +1,5 @@
 # Monitor layout for 14900k.
-# NVIDIA (default): DP-2 ultrawide, HDMI-A-3 + DP-4 side/top stack.
+# NVIDIA (default): DP-3 ultrawide, HDMI-A-3 + DP-4 side/top stack; DP-2 virtual 4K when streamingDisplay enabled.
 # Intel iGPU (gpu passthru): DP-1 ultrawide, HDMI-A-2 Samsung to the left.
 # Niri: `extraSettings` (KDL via `extraConfig`, other wrapper-modules keys) + `extraBinds` (merged keybinds).
 # Hyprland: `chiasson.desktop.hyprland.settings` (merged in HM when `chiasson.desktop.hyprland.enable`).
@@ -8,9 +8,20 @@
 { config, lib, ... }:
 let
   gpuPassthru = config.chiasson.system.gpuPassthru.enable;
+  streamingDisplay = config.chiasson.system.streamingDisplay.enable or false;
+  streamingCfg = config.chiasson.system.streamingDisplay or { };
+
+  virtualOutputNiri =
+    lib.optionalString streamingDisplay ''
+      output "${streamingCfg.connector}" {
+          mode "${streamingCfg.mode}"
+          scale ${toString (streamingCfg.niriScale or 1.0)}
+          position ${streamingCfg.niriPosition}
+      }
+    '';
 
   niriOutputs =
-    if gpuPassthru then
+    (if gpuPassthru then
       ''
         output "DP-1" {
             mode "2560x1080@144"
@@ -42,10 +53,15 @@ let
             scale 1.0
             position x=0 y=-1080
         }
-      '';
+      '')
+    + virtualOutputNiri;
+
+  virtualOutputHyprland =
+    lib.optionalString streamingDisplay
+      "${streamingCfg.connector}, ${streamingCfg.mode}, 7680x0, ${toString (streamingCfg.niriScale or 1.0)}";
 
   hyprlandMonitors =
-    if gpuPassthru then
+    (if gpuPassthru then
       [
         "DP-1, 2560x1080@144, 0x0, 1"
         "HDMI-A-2, 1920x1080@60, -1920x0, 1"
@@ -55,7 +71,8 @@ let
         "DP-3, 2560x1080@144, 0x0, 1"
         "DP-4, 1920x1080@144, 0x-1080, 1"
         "HDMI-A-3, 1920x1080@60, -1920x0, 1"
-      ];
+      ])
+    ++ lib.optional streamingDisplay virtualOutputHyprland;
 
   hyprlandWorkspaces =
     if gpuPassthru then