claude: Align engine template with build-ts-extension system

Remove vendored quarto-types approach and restructure engine template
to match the build-ts-extension specification.

Changes:
- Remove backward compatibility quarto-types copy from prepare-dist.ts
- Remove vendoring logic from artifacts/extension.ts
- Move TypeScript source from _extensions/ to src/ in engine template
- Update _extension.yml to reference .js output instead of .ts
- Update imports to use @quarto/types via import map
- Add build instructions to README
- Fix deno.json to include "deno.ns" in lib array (both default and --init-config)

Engine extensions now follow the spec:
- Source in src/
- Build to _extensions/<name>/<name>.js using build-ts-extension
- Reference types via import map (no vendored copies)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: gordonwoodhull

package/src/common/prepare-dist.ts

@@ -168,14 +168,6 @@ export async function prepareDist(
     );
   }
 
-  // Copy quarto-types for engine extension template (backward compatibility)
-  info("Copying quarto-types.d.ts for engine extension template");
-  copySync(
-    join(config.directoryInfo.root, "packages/quarto-types/dist/index.d.ts"),
-    join(config.directoryInfo.pkgWorking.share, "quarto-types.d.ts"),
-    { overwrite: true },
-  );
-
   // Copy quarto-types to extension-build directory
   // Note: deno.json and import-map.json are copied by supportingFiles() and
   // import-map.json is then updated by updateImportMap() for distribution

src/command/create/artifacts/extension.ts

@@ -256,34 +256,6 @@ async function createExtension(
     quiet,
   );
 
-  // For engine extensions, copy the current quarto-types
-  const createType = typeFromTemplate(createDirective.template);
-  if (createType === "engine") {
-    // Try to find types in the distribution (production)
-    let typesSource = resourcePath("quarto-types.d.ts");
-
-    if (!existsSync(typesSource)) {
-      // Development build - get from source tree
-      const quartoRoot = Deno.env.get("QUARTO_ROOT");
-      if (!quartoRoot) {
-        throw new Error(
-          "Cannot find quarto-types.d.ts. QUARTO_ROOT environment variable not set.",
-        );
-      }
-      typesSource = join(quartoRoot, "packages/quarto-types/dist/index.d.ts");
-    }
-
-    const typesTarget = join(
-      target,
-      "_extensions",
-      createDirective.name,
-      "types",
-      "quarto-types.d.ts",
-    );
-    ensureDirSync(dirname(typesTarget));
-    copySync(typesSource, typesTarget);
-  }
-
   return filesCreated[0];
 }
 

src/command/dev-call/build-ts-extension/cmd.ts

@@ -281,7 +281,7 @@ async function initializeConfig(): Promise<void> {
   const config = {
     compilerOptions: {
       strict: true,
-      lib: ["DOM", "ES2021"],
+      lib: ["deno.ns", "DOM", "ES2021"],
     },
     importMap: importMapPath,
   };

src/resources/create/extensions/engine/README.ejs.md

@@ -13,6 +13,33 @@ quarto add <github-organization>/<%= filesafename %>
 This will install the extension under the `_extensions` subdirectory.
 If you're using version control, you will want to check in this directory.
 
+## Developing
+
+This extension is written in TypeScript. The source code is in the `src/` directory.
+
+### Building
+
+To build the extension, you need to set up the build configuration and then run the build command:
+
+```bash
+# Build the TypeScript source to JavaScript
+quarto dev-call build-ts-extension
+```
+
+This will:
+
+- Type-check your TypeScript code against Quarto's API types
+- Bundle the extension into `_extensions/<%= filesafename %>/<%= filesafename %>.js`
+
+The built JavaScript file should be committed to version control along with the source.
+
+Optionally, you can create a deno.json to further customize the build:
+
+```bash
+# First time setup - creates deno.json with import map configuration
+quarto dev-call build-ts-extension --init-config
+```
+
 ## Using
 
 _TODO_: Describe how to use your extension.

src/resources/create/extensions/engine/_extensions/qstart-filesafename-qend/_extension.ejs.yml

@@ -4,4 +4,4 @@ version: <%= version %>
 quarto-required: ">=<%= quartoversion %>"
 contributes:
   engines:
-    - path: <%= filesafename %>.ts
+    - path: <%= filesafename %>.js

…ame-qend/qstart-filesafename-qend.ejs.ts …gine/src/qstart-filesafename-qend.ejs.tssrc/resources/create/extensions/engine/_extensions/qstart-filesafename-qend/qstart-filesafename-qend.ejs.ts renamed to src/resources/create/extensions/engine/src/qstart-filesafename-qend.ejs.ts src/resources/create/extensions/engine/_extensions/qstart-filesafename-qend/qstart-filesafename-qend.ejs.ts renamed to src/resources/create/extensions/engine/src/qstart-filesafename-qend.ejs.ts

@@ -7,7 +7,7 @@
  * It demonstrates the basic structure of an execution engine.
  */
 
-// Type imports from bundled quarto-types
+// Type imports from Quarto via import map
 import type {
   DependenciesOptions,
   EngineProjectContext,
@@ -19,7 +19,7 @@ import type {
   MappedString,
   PostProcessOptions,
   QuartoAPI,
-} from "./types/quarto-types.d.ts";
+} from "@quarto/types";
 
 // Module-level quarto API reference
 let quarto: QuartoAPI;

src/resources/extension-build/deno.json

@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "strict": true,
-    "lib": ["DOM", "ES2021"]
+    "lib": ["deno.ns", "DOM", "ES2021"]
   },
   "importMap": "./import-map.json"
 }