Upgrading from v0.4.1 requires stopping the whole fleet first.

Highlights:

- Support for Containers and the Cloudflare Sandbox SDK. - Support for worker_loaders in wrangler.json. Loaded Workers can receive service bindings and use a custom outbound fetch handler. - Service bindings now support fetch() on named entrypoints across Workers. - RPC support for default service bindings and nested properties. AbortSignal can pass through RPC calls on the same node. - Choose how long to keep completed Workflow runs, or delete them manually. - Support for .dev.vars in celld dev, with automatic reloads. - Support for WASM files in prebuilt deployments. - Lower memory use per cell and faster KV prefix listings. - Fixes for nested transactions, facet rollback, and unfinished SQL writes. - More reliable alarm delivery and background work after a response. - Database recovery fixes, with lower memory use during recovery and compaction. - Internal host functions are no longer exposed to application code. - Configure telemetry with CELLD_OTEL: 1 for the bucket, or an OTLP collector URL.

Issues fixed:

- #177: Pass service bindings to loaded Workers. - #192: Isolate host state between loaded Workers. - #193: Recover cells after their owner freezes. - #194, #195, #196, #197: Fix Base64 and argument handling. - #198, #199: Fix database compaction and restore failures. - #200: Resume async work when another request wakes it. - #201: Recognize minified imports for Node.js builtins. - #203: Fix duplicate WebSocket Close frames.