feat(scripts): enhance script return structure and context handling

- Introduced a new contract for script returns, requiring an object with `output`, `context`, and `skipRemaining` fields.
- Refactored existing scripts to align with the new return structure, ensuring compatibility with the updated context management.
- Added utility functions for normalizing context and step results, improving the handling of script execution context.
- Updated various scripts (e.g., fetch-binary, fetch-html, fetch-http) to return structured output and context, enhancing data flow and usability.
- Improved error handling for script returns, ensuring clearer feedback when invalid structures are returned.

This update significantly enhances the flexibility and clarity of script interactions within workflows.

packages/server/scripts/fetch-rss-feed.js

@@ -1,10 +1,11 @@
 import rssParser from "rss-parser";
 import jsonata from "jsonata";
 
-function ensureDataObject(ctx) {
-  if (ctx.data == null || typeof ctx.data !== "object" || Array.isArray(ctx.data)) {
-    ctx.data = {};
+function passContext(ctx) {
+  if (ctx?.context != null && typeof ctx.context === "object" && !Array.isArray(ctx.context)) {
+    return { ...ctx.context };
   }
+  return {};
 }
 
 function previewValue(value) {
@@ -28,8 +29,6 @@ async function fetchRssFeed(ctx) {
     throw new Error("fetch-rss-feed: ctx.config.outputVar is required when jsonata is set");
   }
 
-  ensureDataObject(ctx);
-
   log.info({ url }, "fetch-rss-feed: fetching feed");
   const parser = new rssParser({
     customFields: {
@@ -46,7 +45,8 @@ async function fetchRssFeed(ctx) {
     "fetch-rss-feed: fetch complete",
   );
 
-  ctx.data.rssFeed = feed;
+  /** @type {Record<string, unknown>} */
+  const output = { rssFeed: feed };
   log.info(
     { title: feed.title, itemCount },
     "fetch-rss-feed: saved rssFeed",
@@ -56,14 +56,14 @@ async function fetchRssFeed(ctx) {
     log.info({ outputVar, jsonata: jsonataExpr }, "fetch-rss-feed: evaluating jsonata");
     const expression = jsonata(jsonataExpr);
     const result = await expression.evaluate(feed);
-    ctx.data[outputVar] = result;
+    output[outputVar] = result;
     log.info(
       { outputVar, result: previewValue(result) },
       "fetch-rss-feed: saved jsonata result",
     );
   }
 
-  return ctx;
+  return { output, context: { ...passContext(ctx), ...output } };
 }
 
 fetchRssFeed.meta = {
@@ -75,7 +75,7 @@ fetchRssFeed.meta = {
     outputVar: {
       type: "string",
       required: false,
-      description: "Required when jsonata is set; destination on ctx.data",
+      description: "Required when jsonata is set; key on output and context",
     },
     jsonata: {
       type: "string",
@@ -89,6 +89,9 @@ fetchRssFeed.meta = {
   output: {
     rssFeed: { type: "object", description: "Parsed RSS/Atom feed from rss-parser" },
   },
+  context: {
+    rssFeed: { type: "object", description: "Same as output.rssFeed (plus outputVar when set)" },
+  },
   example: {
     data: {},
     config: {