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/locate-path/index.js

@@ -0,0 +1,65 @@
+'use strict';
+const path = require('path');
+const fs = require('fs');
+const {promisify} = require('util');
+const pLocate = require('p-locate');
+
+const fsStat = promisify(fs.stat);
+const fsLStat = promisify(fs.lstat);
+
+const typeMappings = {
+	directory: 'isDirectory',
+	file: 'isFile'
+};
+
+function checkType({type}) {
+	if (type in typeMappings) {
+		return;
+	}
+
+	throw new Error(`Invalid type specified: ${type}`);
+}
+
+const matchType = (type, stat) => type === undefined || stat[typeMappings[type]]();
+
+module.exports = async (paths, options) => {
+	options = {
+		cwd: process.cwd(),
+		type: 'file',
+		allowSymlinks: true,
+		...options
+	};
+	checkType(options);
+	const statFn = options.allowSymlinks ? fsStat : fsLStat;
+
+	return pLocate(paths, async path_ => {
+		try {
+			const stat = await statFn(path.resolve(options.cwd, path_));
+			return matchType(options.type, stat);
+		} catch (_) {
+			return false;
+		}
+	}, options);
+};
+
+module.exports.sync = (paths, options) => {
+	options = {
+		cwd: process.cwd(),
+		allowSymlinks: true,
+		type: 'file',
+		...options
+	};
+	checkType(options);
+	const statFn = options.allowSymlinks ? fs.statSync : fs.lstatSync;
+
+	for (const path_ of paths) {
+		try {
+			const stat = statFn(path.resolve(options.cwd, path_));
+
+			if (matchType(options.type, stat)) {
+				return path_;
+			}
+		} catch (_) {
+		}
+	}
+};