fix(bridge): clean up resources when initialization fails

[forever-ivy]

What

Release the MCP connection and any registered page tools when createWebMcpBridge() fails during its initial tool synchronization.

Why

Once the MCP connection succeeds, a failing tools/list request currently rejects initialization without closing the client. If onRegisterError throws after earlier tools were registered, those registrations also remain active. The caller never receives a bridge instance, so it cannot clean up either resource.

Reuse the existing idempotent close behavior for both explicit closure and failed initialization. Cleanup aborts registrations before closing the client, and a cleanup failure does not replace the original initialization error.

Checks

• npm run check && npm run lint && npm run typecheck && npm test (16 bridge tests and 17 verify tests).
• Both package builds and the bridge's verify:pack check.
• Regression coverage using the MCP SDK's real server and in-memory transports: discovery failure, transport cleanup failure, and partial registration followed by a throwing error handler. The new cases failed before the fix.