fix(gateway): update handshake protocol to v4

[LAIM69420]

Fix gateway handshake compatibility with OpenClaw protocol v4

Closes #361.

What changed

• advertise gateway protocol 4 in the browser WebSocket handshake
• advertise gateway protocol 4 in the server-side RPC handshake
• assert the protocol range in both existing handshake test suites

Why

Current OpenClaw gateways require protocol 4. Nerve advertised only protocol 3 from both connection implementations, so the gateway closed the WebSocket with code 1002 before authentication completed.

Verification

• npx vitest run src/hooks/useWebSocket.test.ts server/lib/gateway-rpc.test.ts — 37 passed
• scoped ESLint — passed
• git diff --check — passed
• full suite — 1,869 passed, 1 unrelated existing failure in server/routes/gateway.test.ts (node:child_process mock has no default export)
• full build remains blocked by existing strict-null TypeScript errors in cron, kanban, sessions, and workspace routes

Summary by CodeRabbit

• Enhancements

  • Updated WebSocket and gateway connections to use protocol version 4 during the connection handshake.
  • Improved compatibility between clients and gateways using the updated protocol range.

• Tests

  • Added coverage to verify that connection handshakes include the required protocol version parameters.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 43543b58-8fba-4f84-a31e-f6162714b5bf

📥 Commits

Reviewing files that changed from the base of the PR and between 312e273 and c36a34b.

📒 Files selected for processing (4)

• server/lib/gateway-rpc.test.ts
• server/lib/gateway-rpc.ts
• src/hooks/useWebSocket.test.ts
• src/hooks/useWebSocket.ts

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📝 Walkthrough

Walkthrough

The WebSocket client and gateway RPC handshake protocol bounds were changed from version 3 to version 4. Client and server handshake tests now assert the updated protocol parameters.

Changes

Protocol v4 handshake

Layer / File(s)	Summary
Align handshake negotiation and coverage src/hooks/useWebSocket.ts, server/lib/gateway-rpc.ts, src/hooks/useWebSocket.test.ts, server/lib/gateway-rpc.test.ts	Client and gateway RPC connections now require protocol version 4, with tests asserting minProtocol: 4 and maxProtocol: 4.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• daggerhashimoto/openclaw-nerve#364 — Directly updates the same protocol v4 handshake parameters and related assertions.
• daggerhashimoto/openclaw-nerve#143 — Modifies the WebSocket connect handshake payload in the same client code path.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly states the main change: updating the gateway handshake protocol to v4.
Description check	✅ Passed	The PR includes What, Why, and Verification details and is mostly complete despite omitting the template's Type of Change and Screenshots sections.
Linked Issues check	✅ Passed	The code updates both handshake paths to protocol 4 and adds tests, matching issue #361's protocol-mismatch fix.
Out of Scope Changes check	✅ Passed	All changes support the handshake version bump; no unrelated code or features were introduced.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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