feat(aionui): Add AionUi AI cowork desktop app (v2.1.4)

Build AionUi from source using bun for dependency fetching and
electron-vite for TypeScript compilation. Native addons
(better-sqlite3, sharp) are compiled against nixpkgs node-gyp.

The package uses a fixed-output derivation for bun install,
electron-vite for the build, and wraps the result with nixpkgs
electron for a fully self-contained runtime.

Also includes desktop entry and icon generation.

README.md

@@ -12,6 +12,7 @@ A custom Nix overlay and flake providing additional packages not found in upstre
 
 | Package | Description | Category |
 |---------|-------------|----------|
+| `aionui` | Free, open-source, Cowork app with AI Agents | AI Coding Agents |
 | `container-use` | Containerized environments for coding agents | AI Coding Agents |
 | `desloppify` | Multi-language codebase health scanner and technical debt tracker for AI agents | AI Coding Agents |
 | `freebuff` | The world's strongest free coding agent | AI Coding Agents |
@@ -106,6 +107,7 @@ nix-overlay/
 │   ├── default.nix             # Binary-cache-friendly overlay
 │   └── shared-nixpkgs.nix      # Dependency-sharing overlay
 ├── packages/                    # Package definitions
+│   ├── aionui/                 # AionUi - AI Cowork desktop app
 │   ├── container-use/          # Containerized environments for coding agents
 │   ├── default/                # Meta-package listing all packages
 │   ├── desloppify/             # Codebase health scanner for AI agents