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/color-convert/index.js

@@ -0,0 +1,81 @@
+const conversions = require('./conversions');
+const route = require('./route');
+
+const convert = {};
+
+const models = Object.keys(conversions);
+
+function wrapRaw(fn) {
+	const wrappedFn = function (...args) {
+		const arg0 = args[0];
+		if (arg0 === undefined || arg0 === null) {
+			return arg0;
+		}
+
+		if (arg0.length > 1) {
+			args = arg0;
+		}
+
+		return fn(args);
+	};
+
+	// Preserve .conversion property if there is one
+	if ('conversion' in fn) {
+		wrappedFn.conversion = fn.conversion;
+	}
+
+	return wrappedFn;
+}
+
+function wrapRounded(fn) {
+	const wrappedFn = function (...args) {
+		const arg0 = args[0];
+
+		if (arg0 === undefined || arg0 === null) {
+			return arg0;
+		}
+
+		if (arg0.length > 1) {
+			args = arg0;
+		}
+
+		const result = fn(args);
+
+		// We're assuming the result is an array here.
+		// see notice in conversions.js; don't use box types
+		// in conversion functions.
+		if (typeof result === 'object') {
+			for (let len = result.length, i = 0; i < len; i++) {
+				result[i] = Math.round(result[i]);
+			}
+		}
+
+		return result;
+	};
+
+	// Preserve .conversion property if there is one
+	if ('conversion' in fn) {
+		wrappedFn.conversion = fn.conversion;
+	}
+
+	return wrappedFn;
+}
+
+models.forEach(fromModel => {
+	convert[fromModel] = {};
+
+	Object.defineProperty(convert[fromModel], 'channels', {value: conversions[fromModel].channels});
+	Object.defineProperty(convert[fromModel], 'labels', {value: conversions[fromModel].labels});
+
+	const routes = route(fromModel);
+	const routeModels = Object.keys(routes);
+
+	routeModels.forEach(toModel => {
+		const fn = routes[toModel];
+
+		convert[fromModel][toModel] = wrapRounded(fn);
+		convert[fromModel][toModel].raw = wrapRaw(fn);
+	});
+});
+
+module.exports = convert;