feat: add wasm-ton package

Implements @bitgo/wasm-ton — a Rust/WASM package for TON blockchain transaction
building, parsing, and address creation.

- Address encoding/decoding/validation using tonlib-core (V3R2, V4R2, V5R1)
- Transaction deserialization from BOC, signable payload extraction, signature placement
- parseTransaction: extracts recipient, amount, memo, Jetton transfers, staking opcodes
- buildTransaction for 5 intents: payment, fillNonce, consolidate, delegate, undelegate
  - delegate/undelegate support 3 staking types: TON_WHALES, SINGLE_NOMINATOR, MULTI_NOMINATOR
- 45 Rust unit tests, 38 TypeScript tests, BitGoJS fixture compatibility

Author: lcovar

.gitignore

@@ -3,3 +3,4 @@ node_modules/
 *.iml
 *.tsbuildinfo
 .cursor/
+scratch/

packages/wasm-ton/.gitignore

@@ -0,0 +1,11 @@
+target/
+node_modules/
+# we actually only track the .ts files
+dist/
+test/*.js
+test/*.d.ts
+js/*.js
+js/*.d.ts
+js/wasm
+.vscode
+.onboarding/

packages/wasm-ton/.mocharc.json

@@ -0,0 +1,5 @@
+{
+  "extensions": ["ts", "tsx", "js", "jsx"],
+  "spec": ["test/**/*.ts"],
+  "node-option": ["import=tsx/esm", "experimental-wasm-modules"]
+}