feat(security,ui): self-host React deps, Tailwind, fonts; strict CSP; local QR; better selection state

Replace CDN React/ReactDOM/Babel with local libs; remove Babel and inline scripts
Build Tailwind locally, add safelist; switch to assets/tailwind.css
Self-host Font Awesome and Inter (CSS + woff2); remove external font CDNs
Implement strict CSP (no unsafe-inline/eval; scripts/styles/fonts from self)
Extract inline handlers; move PWA scripts to external files
Add local QR code generation (qrcode lib) and remove api.qrserver.com
Improve SessionTypeSelector visual selection (highlighted background and ring)
Keep PWA working with service worker and offline assets
Refs: CSP hardening, offline-first, no external dependencies

node_modules/get-caller-file/README.md

@@ -0,0 +1,41 @@
+# get-caller-file
+
+[![Build Status](https://travis-ci.org/stefanpenner/get-caller-file.svg?branch=master)](https://travis-ci.org/stefanpenner/get-caller-file)
+[![Build status](https://ci.appveyor.com/api/projects/status/ol2q94g1932cy14a/branch/master?svg=true)](https://ci.appveyor.com/project/embercli/get-caller-file/branch/master)
+
+This is a utility, which allows a function to figure out from which file it was invoked. It does so by inspecting v8's stack trace at the time it is invoked.
+
+Inspired by http://stackoverflow.com/questions/13227489
+
+*note: this relies on Node/V8 specific APIs, as such other runtimes may not work*
+
+## Installation
+
+```bash
+yarn add get-caller-file
+```
+
+## Usage
+
+Given:
+
+```js
+// ./foo.js
+const getCallerFile = require('get-caller-file');
+
+module.exports = function() {
+  return getCallerFile(); // figures out who called it
+};
+```
+
+```js
+// index.js
+const foo = require('./foo');
+
+foo() // => /full/path/to/this/file/index.js
+```
+
+
+## Options:
+
+* `getCallerFile(position = 2)`: where position is stack frame whos fileName we want.