docs: comprehensive update for sprints 1-9

Update README, ROADMAP, and mdBook to reflect all sprint deliverables:
rich messaging, file transfer, disappearing messages, Go/TypeScript SDKs,
C FFI, mesh networking (identity, store-and-forward, broadcast), and
security hardening. Add 6 new mdBook guides (REPL reference, Go SDK,
TypeScript SDK + browser demo, rich messaging, file transfer, mesh
networking). Check off 16 completed ROADMAP items across phases 3-9.

docs/src/getting-started/wasm.md

@@ -60,11 +60,19 @@ This means the WASM build works in browser environments out of the box.
 For non-browser WASM runtimes (WASI, etc.), you may need to adjust the
 `getrandom` backend.
 
-## Future plans
+## wasm-bindgen and the TypeScript SDK
 
-- **wasm-bindgen JS bindings**: Wrap the WASM-compatible modules with
-  `#[wasm_bindgen]` annotations to provide a native JavaScript/TypeScript API.
-  This would allow web frontends to perform client-side encryption without a
-  server round-trip.
-- **wasm-pack integration**: Publish the WASM module as an npm package for
-  easy consumption in web projects.
+The `wasm-bindgen` JS bindings are now implemented in
+`sdks/typescript/wasm-crypto/`. This provides 13 JavaScript-callable functions
+wrapping the WASM-compatible crypto modules:
+
+```bash
+cd sdks/typescript/wasm-crypto
+wasm-pack build --target web --out-dir ../pkg
+```
+
+The resulting 175 KB WASM bundle is used by the `@quicproquo/client`
+TypeScript SDK and the interactive browser demo.
+
+See the [TypeScript SDK and Browser Demo](typescript-sdk.md) guide for
+full details on building and running the browser demo.