feat: add Arbitrum USDT wallet with USDT fees

.github/workflows/usdt-tests.yml

@@ -0,0 +1,35 @@
+name: USDT Tests
+
+on:
+  pull_request:
+  push:
+    branches: [master, main]
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  usdt-tests:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+      - uses: Swatinem/rust-cache@v2
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libdbus-1-dev pkg-config protobuf-compiler
+      - name: Check formatting
+        run: cargo fmt --check
+      - name: Run USDT tests
+        run: cargo test --locked --lib modules::usdt
+      - name: Check Rust code
+        run: cargo clippy --locked --lib --tests

.gitignore

@@ -24,3 +24,5 @@ bindings/ios/BitkitCore.xcframework.zip
 .claude/worktrees
 *.local.*
 !*.local.template*
+
+/tests/usdt-fork/node_modules/

AGENTS.md

@@ -20,7 +20,7 @@ Android bindings are built and published by `.github/workflows/gradle-publish.ym
 
 ```bash
 cargo test                                     # All tests
-cargo test modules::<module>                   # Single module (scanner, lnurl, onchain, activity, blocktank, boltz, trezor, jade, hardware_wallet, ur, pubky)
+cargo test modules::<module>                   # Single module (scanner, lnurl, onchain, activity, blocktank, boltz, trezor, jade, hardware_wallet, ur, pubky, usdt)
 ```
 
 ## Lint & Format
@@ -35,7 +35,7 @@ Android bindings use ktlint via Gradle plugin (`org.jlleitschuh.gradle.ktlint`),
 ## Architecture
 
 - `src/lib.rs` — UniFFI exports and module re-exports
-- `src/modules/`: core modules: scanner, lnurl, onchain, activity, blocktank, boltz, trezor, jade, hardware_wallet, ur, pubky
+- `src/modules/`: core modules: scanner, lnurl, onchain, activity, blocktank, boltz, trezor, jade, hardware_wallet, ur, pubky, usdt
 - `bindings/` — Platform-specific binding outputs (ios/, android/, python/)
 - `build.sh`, `build_ios.sh`, `build_android.sh`, `build_python.sh` — Build scripts