feat: open landing page on first install

- also when loaded as a temporary extension to make it easier to dev

add-on/src/background/background.js

@@ -1,7 +1,12 @@
 'use strict'
 /* eslint-env browser, webextensions */
 
+const browser = require('webextension-polyfill')
 const createIpfsCompanion = require('../lib/ipfs-companion')
+const onInstalled = require('../lib/on-installed')
+
+// register onInstalled hook early, otherwise we miss first install event
+browser.runtime.onInstalled.addListener(onInstalled)
 
 // init add-on after all libs are loaded
 document.addEventListener('DOMContentLoaded', async () => {

add-on/src/lib/on-installed.js

@@ -0,0 +1,14 @@
+'use strict'
+/* eslint-env browser */
+
+const browser = require('webextension-polyfill')
+
+module.exports = function onRuntimeInstalled (details) {
+  console.log('[ipfs-companion] onInstalled event', details)
+  // details.temporary === run via `npm run firefox`
+  if (details.reason === 'install' || details.temporary) {
+    browser.tabs.create({
+      url: '/dist/landing-pages/welcome/index.html'
+    })
+  }
+}