feat: Helios Booth 2026 — Lit web component voting booth

[benadida-agent]

Summary

• New heliosbooth2026/ directory implementing a complete voting booth using Lit 3.3.x + TypeScript 5.x + Vite 6.x
• Full end-to-end voting flow: election info → question selection → ballot encryption (Web Worker) → review → submit/audit
• 5 screen components (question-screen, review-screen, submit-screen, audit-screen, encrypting-screen) orchestrated by central booth-app state holder
• Accessibility: skip link, ARIA landmarks, focus management, keyboard navigation, high contrast & reduced motion support
• Production-ready: Vite single-bundle build (61 KB JS gzip 17 KB), responsive CSS, error handling with recovery, noscript fallback
• Django URL route at /booth2026/ serves the new booth alongside the existing heliosbooth/

Architecture

• Props-drilling pattern: booth-app holds all state, child components receive data via properties and emit events via CustomEvent with bubbles: true, composed: true
• Encryption: Web Worker (encryption-worker.js) handles ballot encryption in background thread using existing jscrypto libraries
• Crypto libraries: Loaded via synchronous <script> tags (same as existing booth), TypeScript declarations in src/crypto/types.ts
• No runtime dependencies beyond Lit: All crypto handled by existing jscrypto, no additional frameworks

Test Plan

• All 198 Django tests pass
• TypeScript compiles with strict mode (including noUnusedLocals, noUnusedParameters)
• Vite production build succeeds
• No network calls between Start and Submit (offline-capable encryption)
• Manual: Load booth at /booth2026/?election_url=<url>, complete full voting flow
• Manual: Test keyboard-only navigation through entire flow
• Manual: Verify ballot audit (spoil + re-encrypt) works
• Manual: Test on mobile viewport (responsive layout)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Introduces a new Lit + TypeScript + Vite-based “Helios Booth 2026” frontend served alongside the existing booth, including a web-worker-based encryption path and vendored legacy jscrypto libraries.

Changes:

• Added Django route to serve /booth2026/ content from a new heliosbooth2026/ directory.
• Implemented Lit screen components for the voting flow (question/review/encrypting/submit/audit).
• Added a Vite/TS build setup plus vendored crypto libraries and worker-based encryption.

Reviewed changes

Copilot reviewed 34 out of 38 changed files in this pull request and generated 49 comments.

Show a summary per file

File	Description
urls.py	Adds a /booth2026/ static-serving route for the new booth.
heliosbooth2026/index.html	New booth HTML entrypoint loading styles, crypto libs, and app entry.
heliosbooth2026/package.json	Adds Vite/Lit/TS project configuration and build scripts.
heliosbooth2026/package-lock.json	Locks npm dependency graph for the booth.
heliosbooth2026/tsconfig.json	TypeScript compiler configuration for the booth source.
heliosbooth2026/vite.config.ts	Vite build/dev server configuration for /booth2026/ base path.
heliosbooth2026/.gitignore	Ignores node_modules and dist output for the booth project.
heliosbooth2026/src/main.ts	App entry module that registers/initializes the booth app.
heliosbooth2026/src/crypto/types.ts	TS type declarations for global jscrypto/HELIOS APIs and worker messages.
heliosbooth2026/src/styles/booth.css	Base styling for the new booth UI (responsive/contrast/motion).
heliosbooth2026/src/screens/question-screen.ts	Lit question UI with selection and navigation events.
heliosbooth2026/src/screens/review-screen.ts	Lit review UI showing selections, tracker, and cast/audit actions.
heliosbooth2026/src/screens/encrypting-screen.ts	Lit encryption progress UI.
heliosbooth2026/src/screens/submit-screen.ts	Lit submit UI with form POST to cast_url.
heliosbooth2026/src/screens/audit-screen.ts	Lit audit UI for spoiled ballot verification workflow.
heliosbooth2026/workers/encryption-worker.js	Web Worker that imports jscrypto libs and encrypts answers off-thread.
heliosbooth2026/public/loading.gif	Loading indicator asset.
heliosbooth2026/public/encrypting.gif	Encryption indicator asset.
heliosbooth2026/lib/underscore-min.js	Vendored Underscore.js dependency for legacy crypto code.
heliosbooth2026/lib/jscrypto/README	Vendored jscrypto README.
heliosbooth2026/lib/jscrypto/jsbn.js	Vendored jscrypto dependency.
heliosbooth2026/lib/jscrypto/jsbn2.js	Vendored jscrypto dependency.
heliosbooth2026/lib/jscrypto/sjcl.js	Vendored SJCL bundle used by jscrypto.
heliosbooth2026/lib/jscrypto/class.js	Vendored John Resig class helper used by jscrypto.
heliosbooth2026/lib/jscrypto/bigint.js	Vendored BigInt wrapper used by jscrypto.
heliosbooth2026/lib/jscrypto/random.js	Vendored RNG glue used by jscrypto.
heliosbooth2026/lib/jscrypto/elgamal.js	Vendored ElGamal implementation used by Helios crypto.
heliosbooth2026/lib/jscrypto/sha1.js	Vendored SHA-1 implementation used by jscrypto.
heliosbooth2026/lib/jscrypto/sha2.js	Vendored SHA-2 implementation used by jscrypto.
heliosbooth2026/lib/jscrypto/helios.js	Vendored Helios crypto logic (Election/EncryptedVote/etc.).
heliosbooth2026/lib/jscrypto/bigint.java	Vendored Java applet source (legacy BigInt support).
heliosbooth2026/lib/jscrypto/bigint.dummy.js	Vendored dummy BigInt implementation (legacy support).
heliosbooth2026/lib/jscrypto/bigint.class	Vendored Java applet bytecode (legacy BigInt support).
docs/implementation-plans/2026-01-18-helios-booth-lit-redesign/phase_02.md	Documentation plan for Phase 2 voting flow implementation.
docs/implementation-plans/2026-01-18-helios-booth-lit-redesign/phase_04.md	Documentation plan for Phase 4 polish/deployment steps.

Files not reviewed (1)

• heliosbooth2026/package-lock.json: Language not supported

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[Copilot]

do_encrypt assumes ELECTION has been initialized and q_num is valid. If an encrypt message arrives before setup, or q_num is out of bounds, the worker will throw and stop responding. Add guards that post an error response (and/or ignore) when ELECTION is null or the question index is invalid.

[Copilot]

Clicking the checkbox is likely to toggle twice: the <li @click> handler fires, and the <input @change> handler also calls handleAnswerClick. stopPropagation() on the change event doesn’t stop the click bubble. This can result in the selection immediately reverting. Consider handling selection in one place (e.g., only on the input’s @click/@change and remove the <li @click>, or stop propagation on the input’s click event).

[Copilot]

<h4> is being used as an interactive control (@click=${this.toggleAuditSection}) but isn’t keyboard-focusable and doesn’t expose button semantics to assistive tech. Use a <button> (or <details><summary>) for the toggle, or add appropriate role="button", tabindex="0", and key handlers.

[Copilot]

npm run build runs tsc with emit enabled, writing into dist/, and then vite build also outputs to dist/ (and typically clears it first). This makes the tsc output either wasted or potentially conflicting. Consider switching to tsc --noEmit for type-checking, or configure tsc to emit to a separate directory if you actually need declarations.

Suggested change

	"build": "tsc && vite build",
	"build": "tsc --noEmit && vite build",

[Copilot]

With outDir set to ./dist and declaration enabled, tsc will emit build artifacts into the same directory Vite uses for its production output. If the intention is type-check-only before Vite builds, consider disabling emit (noEmit: true) and/or turning off declaration outputs here to avoid churn/overwrites in dist/.

[Copilot]

Avoid automated semicolon insertion (91% of all statements in the enclosing script have an explicit semicolon).

Suggested change

	}
	};

[Copilot]

Avoid automated semicolon insertion (95% of all statements in the enclosing script have an explicit semicolon).

Suggested change

	}
	};

[Copilot]

Avoid automated semicolon insertion (92% of all statements in the enclosing script have an explicit semicolon).

Suggested change

	}
	};

[Copilot]

Avoid automated semicolon insertion (92% of all statements in the enclosing script have an explicit semicolon).

Suggested change

	}
	};

[Copilot]

This use of variable 'USE_SJCL' always evaluates to true.

Suggested change

	// let's try always using SJCL
	var USE_SJCL = true;
	// let's make this much cleaner
	if (USE_SJCL) {
	// why not?
	var BigInt = BigInteger;
	// ZERO AND ONE are already taken care of
	BigInt.TWO = new BigInt("2",10);
	BigInt.setup = function(callback, fail_callback) {
	// nothing to do but go
	callback();
	}
	BigInt.prototype.toJSONObject = function() {
	return this.toString();
	};
	} else {
	BigInt = Class.extend({
	init: function(value, radix) {
	if (value == null) {
	throw "null value!";
	}
	if (USE_SJCL) {
	this._java_bigint = new BigInteger(value, radix);
	} else if (BigInt.use_applet) {
	this._java_bigint = BigInt.APPLET.newBigInteger(value, radix);
	} else {
	try {
	this._java_bigint = new java.math.BigInteger(value, radix);
	} catch (e) {
	// alert("oy " + e.toString() + " value=" + value + " , radix=" + radix);
	throw TypeError
	}
	}
	},
	toString: function() {
	return this._java_bigint.toString() + "";
	},
	toJSONObject: function() {
	return this.toString();
	},
	add: function(other) {
	return BigInt._from_java_object(this._java_bigint.add(other._java_bigint));
	},
	bitLength: function() {
	return this._java_bigint.bitLength();
	},
	mod: function(modulus) {
	return BigInt._from_java_object(this._java_bigint.mod(modulus._java_bigint));
	},
	equals: function(other) {
	return this._java_bigint.equals(other._java_bigint);
	},
	modPow: function(exp, modulus) {
	return BigInt._from_java_object(this._java_bigint.modPow(exp._java_bigint, modulus._java_bigint));
	},
	negate: function() {
	return BigInt._from_java_object(this._java_bigint.negate());
	},
	multiply: function(other) {
	return BigInt._from_java_object(this._java_bigint.multiply(other._java_bigint));
	},
	modInverse: function(modulus) {
	return BigInt._from_java_object(this._java_bigint.modInverse(modulus._java_bigint));
	}
	});
	// Using SJCL-backed BigInteger implementation directly.
	// NOTE: previously this was controlled by a USE_SJCL flag that was always true.
	// let's make this much cleaner
	// why not?
	var BigInt = BigInteger;
	// ZERO AND ONE are already taken care of
	BigInt.TWO = new BigInt("2",10);
	BigInt.setup = function(callback, fail_callback) {
	// nothing to do but go
	callback();
	};
	BigInt.prototype.toJSONObject = function() {
	return this.toString();
	};