Switch desktop environment from Hyprland to Budgie; app/audio overhaul

Hyprland problems prompted a full switch to Budgie (X11, lightdm).
Removes every Hyprland/Quickshell dotfile, theming script, and
hypr-specific module (theme.nix, the whole scripts/ theming pipeline,
hyprland.conf/hyprpaper.conf, the Quickshell shell QML, kitty/mako/
rofi configs) in favor of Budgie's own panel/session/theming and a
GSettings-driven icon/cursor override.

App changes:
- Konsole/Dolphin replace kitty/Thunar as the default terminal and
  file manager; dropped xterm too (services.xserver.excludePackages)
- Added Okular (PDF/document viewer), KCalc (calculator), Elisa
  (audio player) -- nothing filled those roles before
- Added OBS Studio

Audio/voice:
- EasyEffects for real-time mic/output effects (creates its own
  selectable "Easy Effects Source" virtual mic automatically)
- A standalone "Virtual Microphone" PipeWire device (loopback module,
  services.pipewire.extraConfig), fully independent of the real mic,
  for routing EasyEffects/Soundux output separately from what Discord
  etc. use by default
- qpwgraph for manual patchbay routing into the above
- Soundux (soundboard) installed via Flatpak -- no longer packaged in
  this nixpkgs channel

default-apps.nix: Okular wired into mimeapps.list alongside the
existing Gwenview/Ark defaults; removed the Thunar-specific
"Open Terminal Here" custom-action tmpfiles rule (dead now that
Thunar's gone -- Dolphin gets the same via its built-in konsolepart
terminal panel for free).

modules/apps.nix

@@ -1,41 +1,17 @@
 { config, pkgs, ... }:
 
-let
-  # hyprpolkitagent only ships its binary under libexec/, not bin/, so it
-  # never lands on $PATH — wrap it so `exec-once = hyprpolkitagent` in
-  # hyprland.conf can find it.
-  hyprpolkitagentBin = pkgs.writeShellScriptBin "hyprpolkitagent"
-    "exec ${pkgs.hyprpolkitagent}/libexec/hyprpolkitagent";
-in
 {
   # Every installed package — GUI apps, CLI tools, and dev toolchains alike.
   # If it's "install X", it goes here.
   users.users."nexoniarz".packages = with pkgs; [
-    # Hyprland desktop toolchain (Wayland-native, lightweight, squared theme)
-    kitty                     # Terminal
-    thunar                    # File manager
-    thunar-archive-plugin
-    thunar-volman
-    tumbler                   # Thumbnails (paired with services.tumbler.enable)
-    rofi                      # Launcher (Wayland support built in since 2.0)
-    quickshell                # Bar / UI shell
+    tumbler                   # Thumbnails (paired with services.tumbler.enable; also used by Nemo)
+    gnome-screenshot          # Screenshot capture (X11)
     imv                       # Image viewer
-    mako                      # Notification daemon
-    grim                      # Screenshot capture
-    slurp                     # Screenshot region select
-    wl-clipboard               # Wayland clipboard
-    hyprpolkitagentBin        # Polkit authentication agent (wrapped, see `let` above)
-    hyprlock                  # Screen locker (power menu)
     brightnessctl             # Backlight brightness (laptop panels)
     ddcutil                   # DDC/CI brightness (external monitors)
     lm_sensors                # sensors-detect helps ddcutil find I2C buses
-    hyprpaper                 # Wallpaper daemon, driven by the Quickshell picker (static images)
-    mpvpaper                  # Wallpaper daemon for video-loop (animated) wallpapers
     networkmanager            # nmcli, for the Wi-Fi hotspot toggle
     xdg-user-dirs             # Resolves localized folder names (Obrazy, not Pictures, on pl_PL)
-    bibata-cursors            # Cursor theme(s) for the cursor picker
-    xcur2png                  # Renders Xcursor files to PNG for the cursor picker's previews
-    imagemagick                # `identify`, used to pick the right cursor-preview size
     playerctl                  # MPRIS media control, for the function-key media binds
 
     # Apps
@@ -48,6 +24,14 @@ in
     vlc
     filezilla
     chromium
+    obs-studio
+    easyeffects                # Real-time mic/output effects (pitch, EQ, ...) — auto-creates a
+                                # selectable "Easy Effects Source" virtual mic once an Input effect
+                                # is added, no manual PipeWire routing needed
+    qpwgraph                   # Patchbay GUI — wires EasyEffects'/Soundux's output into the
+                                # standalone "Virtual Microphone Sink" (see system.nix)
+    # Soundux (soundboard) isn't packaged in this nixpkgs channel anymore —
+    # installed via Flatpak instead (io.github.Soundux).
 
     # Games
     prismlauncher
@@ -79,6 +63,13 @@ in
     unzip
     unrar
     kdePackages.gwenview
-    kdePackages. kate
+    kdePackages.kate
+    kdePackages.qqc2-desktop-style
+    linphonePackages.linphone-desktop
+    kdePackages.kcalc            # Calculator (nothing filled this role before)
+    kdePackages.okular           # Document/PDF viewer (nothing filled this role before)
+    kdePackages.elisa            # Audio player (vlc/ffmpeg cover video already; nothing dedicated for audio)
+    kdePackages.konsole          # Terminal (replaces kitty)
+    kdePackages.dolphin          # File manager (replaces Thunar, alongside Budgie's default Nemo)
   ];
 }