[hermiondev]

Problem

AlchemyRestClient.request() calls bare fetch() with no signal, and AlchemyRestClientParams exposes no timeout / AbortSignal option — consumers have no legitimate way to bound a request. If the upstream accepts the TCP connection but never responds (saturated LB, half-open keep-alive, captive middleware), the promise never settles.

Reproduced against the published @alchemy/common@5.2.7 dist and against main source with a local never-replying server:

build	behavior
main / 5.2.7 dist (before)	request unsettled past 15s → external watchdog kill (exit 124)
this fix, timeout: 3000 (after)	FetchError: The operation was aborted due to timeout at 3002ms

The JSON-RPC sibling already has this protection — alchemy.ts wraps viem's http() transport, which applies timeout ?? 10_000 via an internal AbortSignal. The REST client is the unprotected sibling.

Fix

• AlchemyRestClientParams gains optional timeout (default 10_000, matching the viem http transport default) and signal (takes precedence when provided).
• request() applies this.signal ?? AbortSignal.timeout(this.timeout) to every fetch; aborts surface through the existing FetchError path — no new error type, no behavior change for healthy upstreams.

Verification

• tsc --noEmit: no new errors vs clean main (5 pre-existing test-mock errors unchanged).
• Live probe vs never-replying server: before = hang forever, after = clean FetchError at the configured timeout.
• No existing consumers are affected (exports for this class are still commented out in index.ts; this hardens the surface before it graduates).

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PR-Codex overview

This PR introduces enhancements to the AlchemyRestClient, adding support for request timeouts and abort signals to improve error handling and prevent indefinite hanging during requests.

Detailed summary

• Added timeout property to specify request timeout in milliseconds.
• Added signal property to allow an AbortSignal for request cancellation.
• Updated the constructor to accept timeout and signal parameters.
• Modified the request method to use the timeout and signal for aborting requests.

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