feat: library / embedded mode

[mnafees]

Description

Adds the ability to spawn an embedded Hatchet engine from a Go SDK client simply by providing a URL to a PostgreSQL DB.

import (
    hatchet "github.com/hatchet-dev/hatchet/sdks/go"

    _ "github.com/hatchet-dev/hatchet/embed"
)

client, err := hatchet.NewClient(hatchet.WithEmbeddedPostgres(databaseURL))
if err != nil {
    return err
}
defer func() { _ = client.Close(context.Background()) }()

This runs a full Hatchet engine (no UI) in-process with the Go binary it is embedded in.

Partially resolves #3680

Type of change

• New feature (non-breaking change which adds functionality)

Checklist

Changes have been:

• Tested (unit, integration, or manually with steps specified)
• Linted and formatted

---

🤖 AI Disclosure

• I acknowledge that an LLM was used in the creation of this Pull Request, in accordance with Hatchet's AI_POLICY.md.

• Details: [e.g. generating tests, writing docs]

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Project	Deployment	Actions	Updated (UTC)
hatchet-docs	Ready	Preview, Comment	Jul 21, 2026 3:34pm

[github-actions]

⚠️ Optional test failure: The load-deadlock job failed on this PR (optimistic-scheduling=true). This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[github-actions]

⚠️ Optional test failure: The load-deadlock job failed on this PR (optimistic-scheduling=true). This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[github-actions]

⚠️ Optional test failure: The load-deadlock job failed on this PR (optimistic-scheduling=false). This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[github-actions]

⚠️ Optional test failure: The load-deadlock job failed on this PR (optimistic-scheduling=false). This check is non-mandatory and does not block merging, but may be worth investigating. View logs

[abelanger5]

Just flagging that there's pretty much no benefit to encryption in this case, so we should likely print a warning to the console (at the very least) when running in this mode.

[abelanger5]

I also wonder if we want to move the embedded keyset management into its own package, and design it similarly to how we did with the pgoutbox schema: https://github.com/hatchet-dev/pgoutbox/blob/main/migrate.go