fix(ci): add missing _docs:api:html npm script

The workflow tried to run _docs:api:html defined in turbo.json, but
the corresponding npm script was missing from package.json. This caused
the docs build to fail silently with 'site/ directory not found' when
upload-pages-artifact tried to archive the output.

Added _docs:api:html script that runs typedoc (configured to output to
site/ via typedoc.json).

Author: Mearman

package.json

@@ -45,7 +45,7 @@
     "schema": "turbo run _schema",
     "test": "turbo run _test",
     "test:coverage": "turbo run _test:coverage",
-    "docs": "turbo run _docs:cli _docs:api",
+    "docs": "turbo run _docs:cli _docs:api:html",
     "docs:serve": "typedoc --watch --serve",
     "lint": "turbo run _lint",
     "spm": "tsx src/cli/index.ts",
@@ -57,6 +57,7 @@
     "_test:coverage": "c8 --src src --exclude 'src/cli/**' --exclude 'src/generate-schema.ts' tsx --test tests/*.test.ts",
     "_docs:cli": "tsx scripts/generate-cli-docs.ts",
     "_docs:api": "typedoc",
+    "_docs:api:html": "typedoc",
     "prepare": "husky"
   },
   "dependencies": {