Re-enable MetadataMergeStage in parse_qmd_to_ast, enable test:ci in CI

- Re-enable MetadataMergeStage in parse_qmd_to_ast so format is injected
  into merged metadata (needed by formatDetection tests and PreviewRouter).
  Remove the commented-out AstTransformsStage entirely — parse_qmd_to_ast
  intentionally returns a pre-transform AST for Elliot's debug renderer.
- Delete stale PreviewRouter.test.ts (file moved to render/ subdirectory,
  test was never visible in CI since test:ci was disabled).
- Uncomment test:ci step in ts-test-suite.yml so hub-client tests run in CI.

Author: gordonwoodhull

.github/workflows/ts-test-suite.yml

@@ -128,8 +128,8 @@ jobs:
           cd hub-client
           npm run build:all
 
-      # - name: Run hub-client tests
-      #   shell: bash
-      #   run: |
-      #     cd hub-client
-      #     npm run test:ci
+      - name: Run hub-client tests
+        shell: bash
+        run: |
+          cd hub-client
+          npm run test:ci

crates/quarto-core/src/pipeline.rs

@@ -297,9 +297,7 @@ pub async fn parse_qmd_to_ast(
     let stages: Vec<Box<dyn PipelineStage>> = vec![
         Box::new(ParseDocumentStage::new()),
         Box::new(EngineExecutionStage::new()),
-        // elliot note: I want this function to give an un-processed AST
-        // Box::new(MetadataMergeStage::new()),
-        // Box::new(AstTransformsStage::new()),
+        Box::new(MetadataMergeStage::new()),
     ];
 
     let (output, warnings) = run_pipeline(content, source_name, ctx, runtime, stages).await?;