feat(sdk,dashboard,docs): U9 — save-time code validation route, SDK type exports, skill doc, step-inversion docs + changeset

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/plugin-sdk/src/index.ts

@@ -96,6 +96,50 @@ export type {
   PluginInstallation,
 } from "@fusion/core";
 
+// ── Step-inversion IR types (type-only) ──────────────────────────────────────
+// TYPE-ONLY re-exports of the workflow-modelable step constructs (KTD-3/12/13/15)
+// so plugin authors can author/validate workflow IR and step parsers against the
+// canonical shapes. These are erased at build time, so the standalone plugin-sdk
+// artifact carries no @fusion runtime specifiers (see cli plugin-sdk-export test).
+export type {
+  // Graph IR primitives.
+  WorkflowIr,
+  WorkflowIrV1,
+  WorkflowIrV2,
+  WorkflowIrNode,
+  WorkflowIrEdge,
+  WorkflowIrNodeKind,
+  // Foreach / artifacts / custom fields (step inversion).
+  WorkflowForeachConfig,
+  WorkflowIrArtifact,
+  WorkflowFieldDefinition,
+  WorkflowFieldType,
+  WorkflowFieldOption,
+  WorkflowFieldRender,
+  // Step-parser contract.
+  StepParser,
+  StepParseResult,
+  ParsedStep,
+} from "@fusion/core";
+
+import type { StepParseResult } from "@fusion/core";
+
+/**
+ * A plugin's step-parser contribution (KTD-12). A plugin's runtime loader returns
+ * these from its `getPluginStepParsers` getter; the engine wraps each fail-closed
+ * and registers it under `plugin:<pluginId>:<parserId>`. `parse` is SYNCHRONOUS
+ * (project-local trust tier) and may throw on malformed input — a throw maps to a
+ * routable `outcome:parse-error`.
+ *
+ * Structurally identical to the engine-side `PluginStepParserContribution` the
+ * plugin runner consumes; defined here so plugin authors do not depend on the
+ * engine package (the SDK depends on @fusion/core only).
+ */
+export interface PluginStepParserContribution {
+  parserId: string;
+  parse: (content: string) => StepParseResult;
+}
+
 import type { FusionPlugin } from "@fusion/core";
 
 // NOTE (U8): trait-contribution VALIDATION lives in @fusion/core