feat/chainstack-rpc-connector

[smypmsa]

Before submitting this PR, please make sure:

• Your code builds clean without any errors or warnings
• You are using approved title ("feat/", "fix/", "docs/", "refactor/")

A description of the changes proposed in the pull request:

Adds Chainstack as a third RPC provider for both Solana and EVM chains, alongside Helius and Infura. Chainstack is the first cross-chain provider for the gateway and the first to use API-driven node discovery instead of URL templating: it calls GET https://api.chainstack.com/v1/nodes once at init and matches the caller's chain/network to a deployed node's https_endpoint / wss_endpoint.

Coverage: 100% of gateway-supported networks — Ethereum, Arbitrum, Polygon, Optimism, Base, Avalanche, BSC, Celo, Sepolia, Solana mainnet, Solana devnet — plus 50+ more available on the platform.

Setup for users:

1. apiKeys.chainstack: '<key>' in apiKeys.yml
2. rpcProvider: chainstack in chains/solana.yml and/or chains/ethereum.yml
3. (optional) preferredNodeId: 'ND-...' in rpc/chainstack.yml to pin a specific deployment

The PR is split into 4 commits for review:

1. Config templates, schemas, apiKeys entry, copy-files glob, live test script
2. ChainstackService (extends RPCProvider) + 18 unit tests
3. Wire Chainstack into the Solana and Ethereum chain constructors
4. Surface the discovered URL in /chains/ethereum/status and the startup banner

Tests performed by the developer:

• pnpm typecheck — clean
• pnpm build — clean
• pnpm lint — 0 errors (259 warnings, same baseline as development)
• pnpm jest --runInBand test/rpc/ test/chains/ethereum test/chains/solana test/services — 268/268 pass
• ChainstackService has 18 dedicated unit tests covering every public method, the network mapping, preferredNodeId selection, and every error path (invalid API key, no matching node, stopped node, unmapped chain)
• Verified the protocol/network mapping table against the live Chainstack Platform API:
  • All 11 rows match get_deployment_options (the authoritative source)
  • Spot-checked with create_node → get_node → delete_node for an EVM chain (arbitrum) and Solana — fields echo back exactly
  • Hit a real https_endpoint with getSlot → returns a valid slot, confirming the URL Chainstack hands out is usable as-is
• Production code uses httpGet / httpPost from src/services/http-client — no axios in src/, consistent with refactor / replace axios with native fetch for HTTP requests #621

Tips for QA testing:

1. Get a Chainstack API key from https://console.chainstack.com/user/settings/api-keys
2. Deploy a node via the Chainstack console (or the Chainstack MCP) for any gateway-supported network
3. Edit conf/apiKeys.yml: chainstack: '<your key>'
4. Edit conf/chains/solana.yml (or ethereum.yml): rpcProvider: chainstack
5. Start the gateway — the startup banner should log Using Chainstack RPC URL: ... with the discovered endpoint
6. Hit GET /chains/solana/status?network=mainnet-beta (or the ethereum equivalent) — rpcUrl in the response should match the Chainstack endpoint, rpcProvider should be chainstack
7. Execute a swap (Jupiter / Raydium / Uniswap) — Solana confirmation flows through the WebSocket monitoring path automatically
8. To test the fallback path: set rpcProvider: chainstack but leave the API key empty — the gateway should log a warning and fall back to nodeURL
9. Optional: pin a specific node by setting preferredNodeId: 'ND-...-...-...' in conf/rpc/chainstack.yml

[fengtality]

Thanks for this PR — solid work overall. Two things worth addressing before merge:

1. instanceof ChainstackService check in solana.ts

The URL swap after init() only triggers via an instanceof check, which leaks the concrete type into the chain layer. The cleanest fix is to add a getHttpUrl() method to the RPCProvider base class (returning null by default) and always swap the connection when it returns a value — removes the special-casing.

2. Duplicated network map

ChainstackService.NETWORK_MAP and GATEWAY_NETWORKS in scripts/test-chainstack-live.js are manually kept in sync (the script even notes this). The test script should import the constant from the service directly to avoid future drift.

Minor (non-blocking):

• getChainstackService() on Ethereum vs getRpcProviderService() on Solana is an inconsistent public API between the two chains — worth aligning
• preferredNodeId should be mentioned in the main config schema or env var docs so users can discover it

[smypmsa]

@fengtality Thanks for the review, addressed all four:

1. getHttpUrl() now lives on the RPCProvider base, returning string | null (default null). ChainstackService overrides to return its discovered URL or null pre-init; Helius/Infura keep returning their templated URL. solana.ts (and ethereum.ts) now always swap the connection when getHttpUrl() returns a non-null value, no more instanceof. Commit: 71a5a50.

2. Added ChainstackService.getSupportedNetworks() as the single source of truth and converted scripts/test-chainstack-live.js to .ts so it imports the static list directly. expectedChainId stays in the script as gateway-side metadata. Commit: 382814b.

3. Replaced getInfuraService() and getChainstackService() on Ethereum with a single polymorphic getRpcProviderService(): RPCProvider | null, symmetric with Solana now. Status routes are provider-agnostic on both chains. Commit: 5de27b9.

4. preferredNodeId was removed in 3b6f7ec per your earlier feedback (you asked us to drop the chainstack namespace, since Helius/Infura don't have one). It's gone from the source, schema, and tests, nothing left to document. If you still see it in your local conf/rpc/chainstack.yml, that's a stale artifact from before the deletion.