WebAssembly bindings for hs-predict.

Exposes three APIs:

• classify_smiles(smiles) — SMILES → functional groups + HS heading hint
• classify_product(product_json) — full rule-based pipeline (Priorities 1–3)
• WasmSession — Akinator-style interactive session

Build with:

wasm-pack build --target web --release

JavaScript usage

import init, { classify_smiles, WasmSession } from './pkg/hs_predict_wasm.js';
await init();

// 1. SMILES classification
const r = classify_smiles('CC(O)=O');
// → { organic_class: "organic", functional_groups: ["CarboxylicAcid"],
//     heading_hint: { chapter: 29, heading: 2915, confidence: 0.6, rationale: "..." } }

// 2. Rule-based pipeline
const pred = classify_product(JSON.stringify({
  identifier: { cas: "1310-73-2" },
  physical_form: "Solid"
}));
// → { hs_code: "281511", confidence: 1.0, ... }

// 3. Interactive session
const session = new WasmSession();
const q1 = session.start();
// → { step: "Identifier", prompt: "Please enter a CAS number...", type: "text" }
const r1 = session.answer(JSON.stringify({ Text: "1310-73-2" }));
// → { type: "NeedMoreInfo", next_question: { step: "IsMixture", ... } }