Activity vocabulary, declarations and lossless history pages. Lifecycle stays in the engine.

Markdown comments shared by the Companion and TUI. Resolved history remains body text.

Pure rules of app attachments: threads, drafts and Send receipts.

An app attachment is a live view with the `attachment` placement. The engine
and the TUI apply these rules to the same engine-shaped maps, so both paint the
same threads and receipts. Every function here is pure: ids, authors and times
come from the caller.

Vis configuration vocabulary and JSON Schema validation.

Canonical content validation from JSON Schema.

Versioned code diffs: the exact patch text and the source it came from.

Loads canonical JSON Schemas and validates payloads against their roots or definitions.
`schema/common.json` supplies shared definitions. Raw validators reject values outside
the JSON data model; engine adapters may normalize keyword maps before validation.

Gateway payload schemas and their HTTP transport metadata.

Renders the gateway payload schemas and HTTP metadata as OpenAPI 3.1.
Extension routes remain in their extension-owned contracts.

Provider limits, model catalog and report validation from JSON Schema.

Feature-toggle vocabulary and contribution validation from JSON Schema.

View vocabulary and JSON Schema validation.

Canonical value and JSON codecs shared by Core, the gateway and every SDK.

This namespace is a pure deterministic boundary: it performs no transport,
filesystem, process or lifecycle work. Engine EDN becomes total JSON data;
in-process readers receive exactly the shape a remote JSON reader receives.