feat(builder): add dynamic blocks email and dnd packages

packages/blocks/src/kinds.ts

@@ -0,0 +1,20 @@
+import type { DocumentLimits, JsonObject } from "./types.ts";
+import type { ValueSchema } from "./schema.ts";
+import type { BlockDefinition } from "./registry.ts";
+
+export interface DocumentKindDefinition {
+  kind: string;
+  version: number;
+  metadata: ValueSchema<JsonObject>;
+  rootTypes: string[];
+  blocks: readonly BlockDefinition[];
+  variables: Record<string, "string" | "number" | "date" | "boolean">;
+  breakpoints: Record<string, number>;
+  capabilities: string[];
+  targets: string[];
+  limits: DocumentLimits;
+  urlSchemes: string[];
+}
+
+export const defineDocumentKind = <T extends DocumentKindDefinition>(definition: T): T =>
+  definition;