[tim-smart]

Adds the Effect 4.1 release post at apps/web/src/content/blog/releases/effect/4.1.mdx, using the same format as the 3.x minor posts: frontmatter, sections for the main features, an "Other changes" list, then the CHANGELOG and Discord links.

4.1.0 isn't tagged yet. v4/next-minor has been merged into Effect-TS/effect main, and the open release PR (Effect-TS/effect#10038) versions effect to 4.1.0. I took the scope from the 58 changesets that PR consumes, at 7ea1ea2ecf (2026-10-28). The highlights are the effect/crypto modules, Glob / FileSystem.glob, CommandLine and Redacted support in ChildProcess, streaming Csv, HttpApi Problem Details, Decision.Image / Decision.locate, Effect.ignore({ log: "Unhandled" }), Pool.stats, ISO 8601 durations, Match.literals and McpServer request-level dependencies and visibility. The breaking changes and upgrade notes come from those same changesets.

Smaller patch fixes are left to the CHANGELOG link at the end of the post: Toml.parse rejecting out-of-range dates, MSSQL cancellation leases, McpServer list-change notifications sent before initialize, CommandLine.template rejecting append assignments, Context.pick keeping maxDepth, KeyValueStore.layerFileSystem remove succeeding for missing keys, and the SQLite hang after an interrupted queued transaction.

All code examples typecheck against 7ea1ea2ecf.

Do not merge until 4.1.0 is published. Pushes to main deploy to production, and the blog index, post routes and RSS include every entry, so merging publishes the announcement.

Before merging:

• date is a placeholder (2026-10-20). Set it to the real release date.
• Recheck the post against the release PR if more changes land before the release.
• tim_smart is the author, the same as on the 3.x minor posts.

The pre-push vp run check fails with 21 errors in SearchDialog.tsx and remark-mermaid.ts. Those errors are already on main and this PR doesn't touch either file. astro sync validates the new content entry.

Closes EFF-2608

[github-actions]

Cloudflare Preview

URL: https://effectwebsite-websiteworker-pr-1638-jz3flqqqos5kfmvu.matechs.workers.dev

Built from commit ff0be71.

---

This comment updates automatically with each deployment.