feat(sdk): add CXX bindings over dash-sdk for C++ embedders

.github/package-filters/rs-packages-direct.yml

@@ -121,6 +121,9 @@ dash-platform-queries:
 dash-sdk:
   - packages/rs-sdk/**
 
+dash-platform-cxx:
+  - packages/rs-platform-cxx/**
+
 rs-sdk-ffi:
   - packages/rs-sdk-ffi/**
 

.github/package-filters/rs-packages-no-workflows.yml

@@ -130,6 +130,17 @@ platform-encryption: &platform_encryption
 dash-platform-queries: &platform_queries
   - packages/dash-platform-queries/**
 
+dash-platform-cxx:
+  - packages/rs-platform-cxx/**
+  - *platform_queries
+  - *context_provider
+  - *dpp
+  - *drive
+  - *dapi_grpc
+  - packages/rs-drive-proof-verifier/**
+  - packages/rs-sdk/**
+  - packages/rs-dapi-client/**
+
 dash-sdk: &sdk
   - packages/rs-drive-proof-verifier/**
   - packages/rs-sdk/**

.github/package-filters/rs-packages.yml

@@ -155,6 +155,18 @@ dash-platform-queries: &platform_queries
   - .github/workflows/tests*
   - packages/dash-platform-queries/**
 
+dash-platform-cxx:
+  - .github/workflows/tests*
+  - packages/rs-platform-cxx/**
+  - *platform_queries
+  - *context_provider
+  - *dpp
+  - *drive
+  - *dapi_grpc
+  - packages/rs-drive-proof-verifier/**
+  - packages/rs-sdk/**
+  - packages/rs-dapi-client/**
+
 dash-sdk: &sdk
   - .github/workflows/tests*
   - packages/rs-drive-proof-verifier/**

.github/workflows/tests-rs-workspace.yml

@@ -226,6 +226,13 @@ jobs:
             done
           done
 
+      # The C++ embedding surface must link and run from the staged headers
+      # and archive alone; the Rust tests cannot see a broken header layout.
+      # (dash-platform-cxx wraps the full dash-sdk, networking included, so it
+      # is deliberately absent from the transport-free cuts above.)
+      - name: Link the Platform CXX embedder from C++
+        run: packages/rs-platform-cxx/scripts/cxx-smoke.sh
+
       - name: Detect immutable structure changes
         if: github.event_name == 'pull_request'
         run: |
@@ -342,6 +349,7 @@ jobs:
             --package rs-sdk-ffi \
             --package platform-wallet-ffi \
             --package rs-dapi-client \
+            --package dash-platform-cxx \
             --package platform-serialization \
             --package dapi-grpc \
             --package json-schema-compatibility-validator \

Cargo.toml

@@ -38,6 +38,7 @@ members = [
     "packages/document-history-contract",
     "packages/keyword-search-contract",
     "packages/rs-sdk-ffi",
+    "packages/rs-platform-cxx",
     "packages/wasm-drive-verify",
     "packages/dash-platform-balance-checker",
     "packages/rs-dapi",

packages/dash-platform-queries/README.md

@@ -27,13 +27,15 @@ downstream code may need to:
 Embedders that bring their own transport and trust context and only need the
 verification/query layer:
 
-- **Dash Core's platform GUI** — fetches over its own gRPC-Web transport,
-  serves quorum keys from its locally synced LLMQ state via a
-  [`ContextProvider`](../rs-context-provider), and verifies every response
-  proof with [`drive-proof-verifier`](../rs-drive-proof-verifier).
 - Block explorers, Electrum-style servers, hardware-wallet tooling — anything
   that talks to DAPI its own way but must not trust responses.
 
+Dash Core's platform GUI consumes the full `dash-sdk` instead, through
+[`dash-platform-cxx`](../rs-platform-cxx): it serves quorum keys from its
+locally synced LLMQ state via a [`ContextProvider`](../rs-context-provider)
+and signatures from its wallet, and lets the SDK own transport, retries and
+proof verification.
+
 If you want networking, retries, and a managed connection pool, use
 `dash-sdk` — it consumes this crate internally.
 

packages/rs-platform-cxx/Cargo.toml

@@ -0,0 +1,51 @@
+[package]
+name = "dash-platform-cxx"
+version.workspace = true
+authors = ["Dash Core Group <dev@dash.org>"]
+edition = "2021"
+rust-version.workspace = true
+license = "MIT"
+description = "CXX bindings over dash-sdk for C++ embedders that supply their own trust context and signing keys"
+
+[lib]
+name = "dash_platform_cxx"
+crate-type = ["staticlib", "rlib"]
+
+[features]
+default = []
+# dash-sdk's mock transport, for tests that replay canned proved responses
+# through the same client code an embedder runs. Never enabled by embedders.
+mocks = ["dash-sdk/mocks"]
+
+[dependencies]
+cxx = "1.0"
+dash-sdk = { path = "../rs-sdk", default-features = false, features = [
+  "dpns-contract",
+  "dashpay-contract",
+] }
+dash-context-provider = { path = "../rs-context-provider", default-features = false }
+dash-platform-queries = { path = "../dash-platform-queries", default-features = false }
+dpp = { path = "../rs-dpp", default-features = false, features = [
+  "state-transitions",
+  "state-transition-signing",
+  "state-transition-validation",
+  "identity-serialization",
+  "identity-hashing",
+  "bls-signatures",
+  "dpns-contract",
+  "dashpay-contract",
+] }
+drive = { path = "../rs-drive", default-features = false, features = ["verify"] }
+platform-version = { path = "../rs-platform-version" }
+tokio = { version = "1.40", features = ["rt-multi-thread", "net", "time"] }
+hex = "0.4"
+futures = "0.3"
+async-trait = "0.1"
+
+[build-dependencies]
+cxx-build = "1.0"
+
+[dev-dependencies]
+dash-platform-cxx = { path = ".", features = ["mocks"] }
+serde_json = "1"
+serde = { version = "1", features = ["derive"] }