feat(discord): add BetterDiscord with gruvbox material dark theme

Restore Discord with OpenASAR overlay and BetterDiscord CSS theming.
Custom gruvbox material dark medium palette with proper read/unread
channel distinction and minimal UI tweaks. Add mpd-discord-rpc for
music rich presence.

home-manager/sajenim/features/cli/mpd.nix

@@ -25,4 +25,17 @@
       }
     '';
   };
+
+  # Discord rich presence for MPD
+  services.mpd-discord-rpc = {
+    enable = true;
+    settings = {
+      hosts = ["localhost:6600"];
+      format = {
+        details = "$title";
+        state = "$artist - $album";
+        timestamp = "elapsed";
+      };
+    };
+  };
 }

home-manager/sajenim/features/desktop/default.nix

@@ -1,6 +1,7 @@
 {pkgs, ...}: {
   imports = [
     ./cava
+    ./discord
     ./mpv
     ./obs
   ];

home-manager/sajenim/features/desktop/discord/config/custom.css

@@ -0,0 +1,95 @@
+:root {
+  --font-primary: Fisa Code;
+
+  /* Gruvbox Material Dark Medium */
+  --bg-dim: #232323;
+  --bg0: #282828;
+  --bg1: #32302f;
+  --bg2: #45403d;
+  --bg3: #5a524c;
+  --bg4: #665c54;
+  --bg5: #7c6f64;
+
+  --fg0: #d4be98;
+  --fg1: #ddc7a1;
+
+  --grey0: #7c6f64;
+  --grey1: #928374;
+  --grey2: #a89984;
+
+  --red: #ea6962;
+  --orange: #e78a4e;
+  --yellow: #d8a657;
+  --green: #a9b665;
+  --aqua: #89b482;
+  --blue: #7daea3;
+  --purple: #d3869b;
+}
+
+.theme-dark {
+  /* Text */
+  --text-default: var(--fg0);               /* main chat */
+  --text-strong: var(--fg1);                /* usernames, selected channel, server accent */
+  --text-subtle: var(--grey2);              /* user status, is typing */
+  --text-muted: var(--grey2);               /* DM friendslist, user status */
+  --white: var(--fg0);
+
+  /* Channels */
+  --channels-default: var(--grey2);         /* read channel text */
+  --channel-icon: var(--grey2);             /* read channel icon */
+  --interactive-text-active: var(--fg1);    /* unread channel text */
+  --icon-subtle: var(--fg1);                /* unread channel icon */
+  --interactive-text-hover: var(--grey2);   /* hovered read channel text */
+
+  /* Other icons */
+  --icon-muted: var(--grey2);
+  --icon-strong: var(--fg1);                /* selected channel */
+  --interactive-icon-default: var(--grey2);
+  --interactive-text-default: var(--grey2);
+
+  /* Placeholders */
+  --channel-text-area-placeholder: var(--grey2);
+  --input-placeholder-text-default: var(--grey2);
+
+  /* Backgrounds */
+  --background-base-lowest: var(--bg-dim);  /* sidebar, channel list, topbar */
+  --background-base-lower: var(--bg0);      /* main chat, member list */
+  --background-base-low: var(--bg0);        /* user panel */
+
+  --background-surface-high: var(--bg1);    /* link previews, server hover, active dm */
+  --background-surface-higher: var(--bg1);  /* active now game/status */
+
+  --background-mod-muted: var(--bg1);       /* active now name bubble */
+  --background-mod-subtle: var(--bg1);      /* server folders, add server */
+  --background-mod-normal: var(--bg2);      /* hover states */
+  --background-mod-strong: var(--bg1);      /* username tag bubbles */
+
+  /* Input */
+  --input-background-default: var(--bg0);   /* search bar input box*/
+  --chat-background-default: var(--bg1);    /* chat input box */
+
+  /* Scrollbar */
+  --scrollbar-thin-thumb: var(--green);
+  --scrollbar-thin-track: transparent;
+  --scrollbar-auto-thumb: var(--green);
+  --scrollbar-auto-track: transparent;
+}
+
+/* Remove input borders */
+[class*="searchBar"],
+[class*="channelTextArea"],
+[class*="textArea"] {
+  border: none !important;
+}
+
+/* Hide server banner and boost goal bar */
+[class*="bannerVisible"],
+[class*="progressContainer"],
+[class*="content"] > [aria-hidden="true"][style*="height"] {
+  display: none !important;
+}
+
+/* Hide new messages bar */
+[class*="newMessagesBar"] {
+  display: none !important;
+}

home-manager/sajenim/features/desktop/discord/default.nix

@@ -0,0 +1,17 @@
+{pkgs, ...}: {
+  nixpkgs.overlays = [
+    (final: prev: {
+      discord = prev.discord.override {withOpenASAR = true;};
+    })
+  ];
+
+  home.packages = with pkgs; [
+    discord
+    betterdiscordctl
+  ];
+
+  home.file.".config/BetterDiscord/data/stable/custom.css" = {
+    enable = true;
+    source = ./config/custom.css;
+  };
+}

home-manager/sajenim/global/default.nix

@@ -21,6 +21,8 @@
       # all allowed packages here rather than scattering predicates across feature modules.
       allowUnfreePredicate = pkg:
         builtins.elem (lib.getName pkg) [
+          "discord"
+
           # Development tools
           "claude-code"
           "idea"