refactor(wallet-cli): enforce RPC param validation at dispatch time via superstruct

[sirtimid]

Summary

Resolves #8777.

• Adds RpcHandler<TParams, TResult>, RpcHandlerDefinition<TParams, TResult> ({ paramsStruct, run }), and a defineHandler(paramsStruct, run) helper in daemon/types.ts. RpcHandlerMap now maps method names to definitions.
• rpc-socket-server.ts validates params against the handler's struct via superstruct.validate before dispatch and returns -32602 invalidParams on shape mismatch. Each handler body can now trust the shape of its argument.
• daemon-entry.ts:
  • getStatus uses literal(null).
  • call uses a defined struct that enforces a non-empty [string, ...Json[]] tuple, dropping the ad-hoc Array.isArray / typeof checks from the handler body.
  • Replaces the wallet.messenger.call as any cast with a single typed RpcDispatcher = messenger.call.bind(messenger) escape hatch.
• Adds @metamask/superstruct ^3.1.0 to wallet-cli (already used across the monorepo at this version).

Test plan

• yarn workspace @metamask/wallet-cli run test — 248 tests pass, 100% line/branch/function/statement coverage on the touched files.
• yarn lint:eslint packages/wallet-cli/src — clean.
• yarn constraints — clean.
• yarn workspace @metamask/wallet-cli run changelog:validate — clean.
• New server test covers the -32602 invalidParams path and verifies run is not invoked when the struct rejects.
• New struct tests on the call handler cover both the rejection cases (null, empty, non-string head, non-array) and the accepting case.

🤖 Generated with Claude Code

---

Note

Medium Risk
Changes the wallet daemon JSON-RPC dispatch path and how malformed params are surfaced (standard invalidParams vs handler errors), on a local socket that still exposes the full messenger surface.

Overview
Daemon RPC handlers are now { paramsStruct, run } definitions (via defineHandler) instead of raw functions. rpc-socket-server validates params with superstruct before calling run and responds with -32602 invalidParams when the shape does not match, so handlers no longer need ad-hoc checks.

daemon-entry wires getStatus / listActions with literal(null), call with a struct for a non-empty [string, ...] action tuple, and routes messenger dispatch through a single RpcDispatcher bind instead of inline casts. Shutdown now logs and continues if dispose() fails during teardown.

Adds @metamask/superstruct and expands tests for invalid-params paths and struct acceptance/rejection.

^{Reviewed by Cursor Bugbot for commit 0c971a5. Bugbot is set up for automated code reviews on this repo. Configure here.}

[rekmarks]

Looks good! Just one thing.

[rekmarks]

@sirtimid actually, since we would have returned different errors prior to this work, we should add a changelog entry for the package.