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/qrcode/bin/qrcode

@@ -0,0 +1,159 @@
+#!/usr/bin/env node
+var yargs = require('yargs')
+var qr = require('../lib')
+
+function save (file, text, options) {
+  qr.toFile(file, text, options, function (err, data) {
+    if (err) {
+      console.error('Error:', err.message)
+      process.exit(1)
+    }
+
+    console.log('saved qrcode to: ' + file + '\n')
+  })
+}
+
+function print (text, options) {
+  options.type = 'terminal'
+  qr.toString(text, options, function (err, text) {
+    if (err) {
+      console.error('Error:', err.message)
+      process.exit(1)
+    }
+
+    console.log(text)
+  })
+}
+
+function parseOptions (args) {
+  return {
+    version: args.qversion,
+    errorCorrectionLevel: args.error,
+    type: args.type,
+    small: !!args.small,
+    inverse: !!args.inverse,
+    maskPattern: args.mask,
+    margin: args.qzone,
+    width: args.width,
+    scale: args.scale,
+    color: {
+      light: args.lightcolor,
+      dark: args.darkcolor
+    }
+  }
+}
+
+function processInputs (text, opts) {
+  if (!text.length) {
+    yargs.showHelp()
+    process.exit(1)
+  }
+
+  if (opts.output) {
+    save(opts.output, text, parseOptions(opts))
+  } else {
+    print(text, parseOptions(opts))
+  }
+}
+
+var argv = yargs
+  .detectLocale(false)
+  .usage('Usage: $0 [options] <input string>')
+  .option('v', {
+    alias: 'qversion',
+    description: 'QR Code symbol version (1 - 40)',
+    group: 'QR Code options:',
+    type: 'number'
+  })
+  .option('e', {
+    alias: 'error',
+    description: 'Error correction level',
+    choices: ['L', 'M', 'Q', 'H'],
+    group: 'QR Code options:'
+  })
+  .option('m', {
+    alias: 'mask',
+    description: 'Mask pattern (0 - 7)',
+    group: 'QR Code options:',
+    type: 'number'
+  })
+  .option('t', {
+    alias: 'type',
+    description: 'Output type',
+    choices: ['png', 'svg', 'utf8'],
+    implies: 'output',
+    group: 'Renderer options:'
+  })
+  .option('i', {
+    alias: 'inverse',
+    type: 'boolean',
+    description: 'Invert colors',
+    group: 'Renderer options:'
+  })
+  .option('w', {
+    alias: 'width',
+    description: 'Image width (px)',
+    conflicts: 'scale',
+    group: 'Renderer options:',
+    type: 'number'
+  })
+  .option('s', {
+    alias: 'scale',
+    description: 'Scale factor',
+    conflicts: 'width',
+    group: 'Renderer options:',
+    type: 'number'
+  })
+  .option('q', {
+    alias: 'qzone',
+    description: 'Quiet zone size',
+    group: 'Renderer options:',
+    type: 'number'
+  })
+  .option('l', {
+    alias: 'lightcolor',
+    description: 'Light RGBA hex color',
+    group: 'Renderer options:'
+  })
+  .option('d', {
+    alias: 'darkcolor',
+    description: 'Dark RGBA hex color',
+    group: 'Renderer options:'
+  })
+  .option('small', {
+    type: 'boolean',
+    description: 'Output smaller QR code to terminal',
+    conflicts: 'type',
+    group: 'Renderer options:'
+  })
+  .option('o', {
+    alias: 'output',
+    description: 'Output file'
+  })
+  .help('h')
+  .alias('h', 'help')
+  .version()
+  .example('$0 "some text"', 'Draw in terminal window')
+  .example('$0 -o out.png "some text"', 'Save as png image')
+  .example('$0 -d F00 -o out.png "some text"', 'Use red as foreground color')
+  .parserConfiguration({'parse-numbers': false})
+  .argv
+
+if (process.stdin.isTTY) {
+  processInputs(argv._.join(' '), argv)
+} else {
+  var text = ''
+  process.stdin.setEncoding('utf8')
+  process.stdin.on('readable', function () {
+    var chunk = process.stdin.read()
+    if (chunk !== null) {
+      text += chunk
+    }
+  })
+
+  process.stdin.on('end', function () {
+    // this process can be run as a command outside of a tty so if there was no
+    // data on stdin read from argv
+    processInputs(text.length?text:argv._.join(' '), argv)
+  })
+}