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/set-blocking/README.md

@@ -0,0 +1,31 @@
+# set-blocking
+
+[![Build Status](https://travis-ci.org/yargs/set-blocking.svg)](https://travis-ci.org/yargs/set-blocking)
+[![NPM version](https://img.shields.io/npm/v/set-blocking.svg)](https://www.npmjs.com/package/set-blocking)
+[![Coverage Status](https://coveralls.io/repos/yargs/set-blocking/badge.svg?branch=)](https://coveralls.io/r/yargs/set-blocking?branch=master)
+[![Standard Version](https://img.shields.io/badge/release-standard%20version-brightgreen.svg)](https://github.com/conventional-changelog/standard-version)
+
+set blocking `stdio` and `stderr` ensuring that terminal output does not truncate.
+
+```js
+const setBlocking = require('set-blocking')
+setBlocking(true)
+console.log(someLargeStringToOutput)
+```
+
+## Historical Context/Word of Warning
+
+This was created as a shim to address the bug discussed in [node #6456](https://github.com/nodejs/node/issues/6456). This bug crops up on
+newer versions of Node.js (`0.12+`), truncating terminal output.
+
+You should be mindful of the side-effects caused by using `set-blocking`:
+
+* if your module sets blocking to `true`, it will effect other modules
+  consuming your library. In [yargs](https://github.com/yargs/yargs/blob/master/yargs.js#L653) we only call
+  `setBlocking(true)` once we already know we are about to call `process.exit(code)`.
+* this patch will not apply to subprocesses spawned with `isTTY = true`, this is
+  the [default `spawn()` behavior](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options).
+
+## License
+
+ISC