Add postinstall script

Author: KennethWussmann

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@ketrwu/simplelogin-cli",
   "description": "Unofficial SimpleLogin CLI",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "author": "Kenneth Wußmann",
   "bin": {
     "sl": "./bin/run.js"
@@ -45,7 +45,8 @@
   "files": [
     "./bin",
     "./dist",
-    "./oclif.manifest.json"
+    "./oclif.manifest.json",
+    "./scripts"
   ],
   "homepage": "https://github.com/KennethWussmann/simplelogin-cli",
   "license": "MIT",
@@ -66,6 +67,7 @@
     "build": "shx rm -rf dist && tsc -b",
     "build:watch": "shx rm -rf dist && tsc -b -w",
     "lint": "eslint",
+    "postinstall": "node scripts/postinstall.js",
     "postpack": "shx rm -f oclif.manifest.json",
     "pack:tarballs": "oclif pack tarballs",
     "posttest": "pnpm run lint",

scripts/postinstall.js

@@ -0,0 +1,31 @@
+#!/usr/bin/env node
+
+console.log(`
+┌─────────────────────────────────────────────────────────────┐
+│                                                             │
+│   ✓ SimpleLogin CLI installed successfully!                 │
+│                                                             │
+│   Note: This is an unofficial CLI tool, not provided by     │
+│   the official SimpleLogin team.                            │
+│                                                             │
+│   Need your API key?                                        │
+│   https://app.simplelogin.io/dashboard/api_key              │
+│                                                             │
+│   Documentation & Bug Reports:                              │
+│   https://github.com/KennethWussmann/simplelogin-cli        │
+│                                                             │
+├─────────────────────────────────────────────────────────────┤
+│                                                             │
+│   Get started in 3 steps:                                   │
+│                                                             │
+│   1. Authenticate:                                          │
+│      $ sl login                                             │
+│                                                             │
+│   2. Create your first alias:                               │
+│      $ sl alias create --note "My first alias"              │
+│                                                             │
+│   3. Explore all commands:                                  │
+│      $ sl help                                              │
+│                                                             │
+└─────────────────────────────────────────────────────────────┘
+`);