Collapse 26 trivial single-package programs into home/programs/common.nix

Consolidates alacritty, audacity, blender, blockbench, claude-code, fd,
filezilla, fzf, gcc, godot_4, imv, jdk21, jetbrains-toolbox, lazygit,
lua-language-server, mpv, nil, nixpkgs-fmt, nodejs, obsidian, pkg-config,
prismlauncher, vesktop, xclip, xwallpaper, yt-dlp into a single list.

rustup.nix kept separate due to its configuration (session vars, many deps).

Updates imports:
- hivebrain: all 26 + rustup now via common.nix + rustup.nix
- nikita-nixos: blender.nix → common.nix (gets all lightweight tools)

home/programs/common.nix

@@ -0,0 +1,31 @@
+{ pkgs, ... }:
+{
+  home.packages = with pkgs; [
+    alacritty
+    audacity
+    blender
+    blockbench
+    claude-code
+    fd
+    filezilla
+    fzf
+    gcc
+    godot_4
+    imv
+    jdk21
+    jetbrains-toolbox
+    lazygit
+    lua-language-server
+    mpv
+    nil
+    nixpkgs-fmt
+    nodejs
+    obsidian
+    pkg-config
+    prismlauncher
+    vesktop
+    xclip
+    xwallpaper
+    yt-dlp
+  ];
+}