Upgrade: zod is a peer dependency of the runtime and store packages

@helix-agents/runtime-cloudflare, @helix-agents/runtime-js and @helix-agents/store-cloudflare no longer bundle their own copy of zod. They now declare zod as a peer dependency, so a Worker loads one copy instead of several.

What to do

Install zod alongside these packages:

pnpm add zod@^4.1.8

Every install that works today already satisfies this, because @helix-agents/core requires zod ^4.1.8 as a peer. If your lockfile resolves zod once, there is nothing else to do.

Why

Each bundled copy of zod costs startup time and memory in a Worker, and a schema built by one copy failed instanceof ZodError checks against another. With one copy, instanceof ZodError and zod class identity work across all Helix packages.

What else changed

• @helix-agents/runtime-js now lists immer as a dependency instead of inlining it. Nothing to install.
• Every published package except @helix-agents/runtime-dbos declares "sideEffects": false, so bundlers can drop unused exports.

No API changes.