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/route.js

@@ -0,0 +1,97 @@
+const conversions = require('./conversions');
+
+/*
+	This function routes a model to all other models.
+
+	all functions that are routed have a property `.conversion` attached
+	to the returned synthetic function. This property is an array
+	of strings, each with the steps in between the 'from' and 'to'
+	color models (inclusive).
+
+	conversions that are not possible simply are not included.
+*/
+
+function buildGraph() {
+	const graph = {};
+	// https://jsperf.com/object-keys-vs-for-in-with-closure/3
+	const models = Object.keys(conversions);
+
+	for (let len = models.length, i = 0; i < len; i++) {
+		graph[models[i]] = {
+			// http://jsperf.com/1-vs-infinity
+			// micro-opt, but this is simple.
+			distance: -1,
+			parent: null
+		};
+	}
+
+	return graph;
+}
+
+// https://en.wikipedia.org/wiki/Breadth-first_search
+function deriveBFS(fromModel) {
+	const graph = buildGraph();
+	const queue = [fromModel]; // Unshift -> queue -> pop
+
+	graph[fromModel].distance = 0;
+
+	while (queue.length) {
+		const current = queue.pop();
+		const adjacents = Object.keys(conversions[current]);
+
+		for (let len = adjacents.length, i = 0; i < len; i++) {
+			const adjacent = adjacents[i];
+			const node = graph[adjacent];
+
+			if (node.distance === -1) {
+				node.distance = graph[current].distance + 1;
+				node.parent = current;
+				queue.unshift(adjacent);
+			}
+		}
+	}
+
+	return graph;
+}
+
+function link(from, to) {
+	return function (args) {
+		return to(from(args));
+	};
+}
+
+function wrapConversion(toModel, graph) {
+	const path = [graph[toModel].parent, toModel];
+	let fn = conversions[graph[toModel].parent][toModel];
+
+	let cur = graph[toModel].parent;
+	while (graph[cur].parent) {
+		path.unshift(graph[cur].parent);
+		fn = link(conversions[graph[cur].parent][cur], fn);
+		cur = graph[cur].parent;
+	}
+
+	fn.conversion = path;
+	return fn;
+}
+
+module.exports = function (fromModel) {
+	const graph = deriveBFS(fromModel);
+	const conversion = {};
+
+	const models = Object.keys(graph);
+	for (let len = models.length, i = 0; i < len; i++) {
+		const toModel = models[i];
+		const node = graph[toModel];
+
+		if (node.parent === null) {
+			// No possible conversion, or this node is the source model.
+			continue;
+		}
+
+		conversion[toModel] = wrapConversion(toModel, graph);
+	}
+
+	return conversion;
+};
+