ci: add FFI verification workflows for Python, Kotlin, Swift, and Flutter

Author: callebtc

.github/workflows/ffi-flutter.yml

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+name: FFI - Flutter Bindings
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  verify-flutter:
+    name: Verify Flutter Bindings
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout CDK
+        uses: actions/checkout@v4
+        with:
+          path: cdk
+
+      - name: Checkout CDK Flutter
+        uses: actions/checkout@v4
+        with:
+          repository: cashubtc/cdk_flutter
+          path: cdk-flutter
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          channel: 'stable'
+
+      - name: Patch Cargo Dependency
+        run: |
+          cd cdk-flutter/rust
+          # Replace crates.io version with local path
+          # Matches: cdk = { version = "..."... } and replaces with cdk = { path = "../../cdk", ... }
+          sed -i 's/^cdk = { version = "[^"]*",/cdk = { path = "..\/..\/cdk",/' Cargo.toml
+          
+          # Verify the change
+          grep "^cdk =" Cargo.toml
+
+      - name: Verify Compilation
+        run: |
+          cd cdk-flutter/rust
+          # Check ensures that the rust code compiles against the local CDK
+          cargo check

.github/workflows/ffi-kotlin.yml

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+name: FFI - Kotlin Bindings
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  verify-kotlin:
+    name: Verify Kotlin Bindings
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout CDK
+        uses: actions/checkout@v4
+        with:
+          path: cdk
+
+      - name: Checkout CDK Kotlin
+        uses: actions/checkout@v4
+        with:
+          repository: cashubtc/cdk-kotlin
+          path: cdk-kotlin
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install Just
+        uses: extractions/setup-just@v1
+
+      - name: Set up Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+
+      - name: Generate Bindings
+        run: |
+          cd cdk-kotlin
+          # cdk-kotlin justfile expects CDK at ../cdk by default
+          just generate
+
+      - name: Verify Compilation
+        run: |
+          cd cdk-kotlin
+          # Fast check: compiles the code without running emulator tests
+          just test-compile

.github/workflows/ffi-python.yml

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+name: FFI - Python Bindings
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  verify-python:
+    name: Verify Python Bindings
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout CDK
+        uses: actions/checkout@v4
+        with:
+          path: cdk
+
+      - name: Checkout CDK Python
+        uses: actions/checkout@v4
+        with:
+          repository: cashubtc/cdk-python
+          path: cdk-python
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install Just
+        uses: extractions/setup-just@v1
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install uv
+        run: pip install uv
+
+      - name: Generate Bindings
+        run: |
+          cd cdk
+          # Builds cdk-ffi and generates python bindings to target/bindings/python
+          just ffi-generate-python
+
+      - name: Install and Verify
+        run: |
+          # Copy generated bindings to cdk-python source
+          cp cdk/target/bindings/python/cdk.py cdk-python/src/cdk/
+          cp cdk/target/bindings/python/libcdk_ffi.so cdk-python/src/cdk/
+          
+          # Install and Test
+          cd cdk-python
+          uv venv
+          source .venv/bin/activate
+          uv pip install -e .[dev]
+          pytest

.github/workflows/ffi-swift.yml

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+name: FFI - Swift Bindings
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  verify-swift:
+    name: Verify Swift Bindings
+    runs-on: macos-latest
+    steps:
+      - name: Checkout CDK
+        uses: actions/checkout@v4
+        with:
+          path: cdk
+
+      - name: Checkout CDK Swift
+        uses: actions/checkout@v4
+        with:
+          repository: cashubtc/cdk-swift
+          path: cdk-swift
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install Just
+        uses: extractions/setup-just@v1
+
+      - name: Generate Bindings
+        run: |
+          cd cdk-swift
+          # Point to the local cdk checkout
+          export CDK_DIR=../cdk
+          just generate
+
+      - name: Verify Build
+        run: |
+          cd cdk-swift
+          export CDK_DIR=../cdk
+          # build-native builds for the current platform (macOS) which is faster
+          just build-native