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/find-up/index.js

@@ -0,0 +1,89 @@
+'use strict';
+const path = require('path');
+const locatePath = require('locate-path');
+const pathExists = require('path-exists');
+
+const stop = Symbol('findUp.stop');
+
+module.exports = async (name, options = {}) => {
+	let directory = path.resolve(options.cwd || '');
+	const {root} = path.parse(directory);
+	const paths = [].concat(name);
+
+	const runMatcher = async locateOptions => {
+		if (typeof name !== 'function') {
+			return locatePath(paths, locateOptions);
+		}
+
+		const foundPath = await name(locateOptions.cwd);
+		if (typeof foundPath === 'string') {
+			return locatePath([foundPath], locateOptions);
+		}
+
+		return foundPath;
+	};
+
+	// eslint-disable-next-line no-constant-condition
+	while (true) {
+		// eslint-disable-next-line no-await-in-loop
+		const foundPath = await runMatcher({...options, cwd: directory});
+
+		if (foundPath === stop) {
+			return;
+		}
+
+		if (foundPath) {
+			return path.resolve(directory, foundPath);
+		}
+
+		if (directory === root) {
+			return;
+		}
+
+		directory = path.dirname(directory);
+	}
+};
+
+module.exports.sync = (name, options = {}) => {
+	let directory = path.resolve(options.cwd || '');
+	const {root} = path.parse(directory);
+	const paths = [].concat(name);
+
+	const runMatcher = locateOptions => {
+		if (typeof name !== 'function') {
+			return locatePath.sync(paths, locateOptions);
+		}
+
+		const foundPath = name(locateOptions.cwd);
+		if (typeof foundPath === 'string') {
+			return locatePath.sync([foundPath], locateOptions);
+		}
+
+		return foundPath;
+	};
+
+	// eslint-disable-next-line no-constant-condition
+	while (true) {
+		const foundPath = runMatcher({...options, cwd: directory});
+
+		if (foundPath === stop) {
+			return;
+		}
+
+		if (foundPath) {
+			return path.resolve(directory, foundPath);
+		}
+
+		if (directory === root) {
+			return;
+		}
+
+		directory = path.dirname(directory);
+	}
+};
+
+module.exports.exists = pathExists;
+
+module.exports.sync.exists = pathExists.sync;
+
+module.exports.stop = stop;