fix(astrolabe): load pdfjs-dist externally to fix PDF viewer

When viewing PDF chunks in semantic search, the PDF viewer failed with
"can't access private field" errors. This was caused by:

1. CSP blocks web workers (worker-src 'none'), forcing fake worker mode
2. Vite transforms ES private fields in the bundle, but the worker file
   is untransformed, causing incompatible private field implementations
3. Vue's ref() wraps PDFDocumentProxy in a Proxy, which can't access
   ES private fields

Fixed by:
- Loading pdfjs-dist externally via script tag (avoids Vite transform)
- Creating pdfjs-loader.mjs that imports pdf.mjs and sets window.pdfjsLib
- Using Util::addScript() for CSP-compliant script loading with nonces
- Using shallowRef() instead of ref() for pdfDoc to avoid Proxy wrapper
- Setting workerSrc at runtime using OC.linkTo() for correct app path

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

third_party/astrolabe/src/App.vue

@@ -394,18 +394,6 @@ import MarkdownViewer from './components/MarkdownViewer.vue'
 import axios from '@nextcloud/axios'
 import { generateUrl } from '@nextcloud/router'
 import Plotly from 'plotly.js-dist-min'
-import * as pdfjsLib from 'pdfjs-dist'
-
-// Set worker source with error handling
-try {
-	pdfjsLib.GlobalWorkerOptions.workerSrc = new URL(
-		'pdfjs-dist/build/pdf.worker.mjs',
-		import.meta.url,
-	).toString()
-} catch (e) {
-	console.warn('Failed to set PDF.js worker, will use fallback', e)
-	// PDF.js will use fake worker automatically
-}
 
 export default {
 	name: 'App',

third_party/astrolabe/src/components/PDFViewer.vue

@@ -15,11 +15,14 @@
 </template>
 
 <script setup>
-import { ref, watch, onMounted, onBeforeUnmount, nextTick } from 'vue'
-import * as pdfjsLib from 'pdfjs-dist'
+import { ref, shallowRef, watch, onMounted, onBeforeUnmount, nextTick } from 'vue'
 import { generateUrl } from '@nextcloud/router'
 import { translate as t } from '@nextcloud/l10n'
 import { NcLoadingIcon } from '@nextcloud/vue'
+
+// Use global pdfjsLib loaded by pdfjs-loader.mjs (external, not bundled)
+// This avoids Vite transforming ES private fields which breaks fake worker compatibility
+const pdfjsLib = window.pdfjsLib
 import AlertCircle from 'vue-material-design-icons/AlertCircle.vue'
 
 const props = defineProps({
@@ -40,7 +43,9 @@ const props = defineProps({
 const emit = defineEmits(['loaded', 'error', 'page-rendered'])
 
 // Reactive state
-const pdfDoc = ref(null)
+// Use shallowRef for pdfDoc because PDFDocumentProxy uses ES private fields
+// which can't be accessed through Vue's Proxy wrapper
+const pdfDoc = shallowRef(null)
 const loading = ref(true)
 const error = ref(null)
 const totalPages = ref(0)
@@ -60,6 +65,10 @@ async function loadPDF() {
 		const encodedPath = cleanPath.split('/').map(encodeURIComponent).join('/')
 		const downloadUrl = generateUrl(`/remote.php/webdav/${encodedPath}`)
 
+		// Set worker source using OC.linkTo for correct app webroot path
+		// Must be done here (not at module load time) because _oc_appswebroots isn't populated until after page load
+		pdfjsLib.GlobalWorkerOptions.workerSrc = window.OC.linkTo('astrolabe', 'js/pdf.worker.mjs')
+
 		// Load PDF document
 		const loadingTask = pdfjsLib.getDocument({
 			url: downloadUrl,