feat: Sprint 8 — TypeScript SDK with WASM crypto and browser demo

- WASM crypto bundle (175KB): 13 wasm_bindgen functions wrapping
  quicproquo-core's Ed25519 identity, X25519+ML-KEM-768 hybrid KEM,
  safety numbers, sealed sender, and message padding
- @quicproquo/client TypeScript SDK: QpqClient class with connect,
  health, resolveUser, createChannel, send/sendWithTTL, receive,
  deleteAccount; WebSocket transport with request/response correlation
  and reconnection; ergonomic crypto.ts wrapper over WASM functions
- Browser demo: vanilla HTML page with interactive crypto operations
  (identity gen, safety numbers, sign/verify, hybrid encrypt/decrypt,
  sealed sender, padding) and chat UI for server connectivity
- Offline mode: crypto operations work without server connection

TypeScript strict mode, 0 errors. WASM bundle size optimized (lto + opt-level=s).

sdks/typescript/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@quicproquo/client",
+  "version": "0.1.0",
+  "type": "module",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "typescript": "^5.0.0"
+  }
+}