fix(reader): patch embedpdf zoom to release startup gate on custom zoom

Apply a patch to @embedpdf/plugin-zoom@2.15.0 so numeric default zoom levels release the startup
viewport gate once resize metrics are measured.

Add unit test to verify custom zoom initialization and scale calculation under EmbedPDF.

Closes #1126

client/src/features/reader/pdf-v4/__tests__/embedpdf-zoom.spec.ts

@@ -0,0 +1,68 @@
+import { afterEach, describe, expect, it } from 'vitest'
+import { PluginRegistry, setDocumentLoaded, startLoadingDocument } from '@embedpdf/core'
+import { Rotation, type PdfDocumentObject, type PdfEngine } from '@embedpdf/models'
+import { ScrollPluginPackage, ScrollStrategy } from '@embedpdf/plugin-scroll'
+import { ViewportPlugin, ViewportPluginPackage } from '@embedpdf/plugin-viewport'
+import { ZoomPlugin, ZoomPluginPackage } from '@embedpdf/plugin-zoom'
+
+describe('patched EmbedPDF custom zoom initialization', () => {
+  let registry: PluginRegistry | null = null
+
+  afterEach(async () => {
+    await registry?.destroy()
+    registry = null
+  })
+
+  it('applies a numeric default zoom and releases the startup gate after viewport measurement', async () => {
+    registry = new PluginRegistry({} as PdfEngine)
+    registry.registerPlugin(ViewportPluginPackage, { viewportGap: 12 })
+    registry.registerPlugin(ScrollPluginPackage, {
+      defaultStrategy: ScrollStrategy.Vertical,
+      defaultPageGap: 12,
+      defaultBufferSize: 3,
+    })
+    registry.registerPlugin(ZoomPluginPackage, {
+      defaultZoomLevel: 1.2,
+      minZoom: 0.25,
+      maxZoom: 4,
+    })
+    await registry.initialize()
+
+    const store = registry.getStore()
+    const documentId = 'custom-zoom-document'
+    const document: PdfDocumentObject = {
+      id: documentId,
+      pageCount: 1,
+      pages: [{ index: 0, size: { width: 600, height: 800 }, rotation: Rotation.Degree0, objectNumber: 1 }],
+      isEncrypted: false,
+      isOwnerUnlocked: true,
+      permissions: 0,
+      normalizedRotation: true,
+    }
+
+    store.dispatchToCore(startLoadingDocument(documentId, 'PDF'))
+    store.dispatchToCore(setDocumentLoaded(documentId, document))
+
+    const viewport = registry.getPlugin<ViewportPlugin>(ViewportPlugin.id)
+    const zoom = registry.getPlugin<ZoomPlugin>(ZoomPlugin.id)
+    expect(viewport?.provides().hasGate('zoom', documentId)).toBe(true)
+
+    viewport?.setViewportResizeMetrics(documentId, {
+      width: 1000,
+      height: 700,
+      clientWidth: 1000,
+      clientHeight: 700,
+      scrollTop: 0,
+      scrollLeft: 0,
+      scrollWidth: 1000,
+      scrollHeight: 700,
+      clientLeft: 0,
+      clientTop: 0,
+    })
+    await new Promise((resolve) => setTimeout(resolve, 175))
+
+    expect(viewport?.provides().hasGate('zoom', documentId)).toBe(false)
+    expect(zoom?.provides().forDocument(documentId).getState()).toMatchObject({ zoomLevel: 1.2, currentZoomLevel: 1.2 })
+    expect(store.getState().core.documents[documentId]?.scale).toBe(1.2)
+  })
+})

patches/@embedpdf__plugin-zoom@2.15.0.patch

@@ -0,0 +1,15 @@
+diff --git a/dist/index.js b/dist/index.js
+index f33d50ed18a00f00cba6b102f5e7ab18f141364e..bb9085c18a295b7ac1e621423e94652803a647fc 100644
+--- a/dist/index.js
++++ b/dist/index.js
+@@ -609,6 +609,10 @@ const _ZoomPlugin = class _ZoomPlugin extends BasePlugin {
+   recalcAuto(documentId, focus) {
+     const docState = this.getDocumentState(documentId);
+     if (!docState) return;
++    if (typeof docState.zoomLevel === "number") {
++      if (this.viewport.hasGate("zoom", documentId)) this.handleRequest({ level: docState.zoomLevel, focus }, documentId);
++      return;
++    }
+     if (docState.zoomLevel === ZoomMode.Automatic || docState.zoomLevel === ZoomMode.FitPage || docState.zoomLevel === ZoomMode.FitWidth) {
+       this.handleRequest({ level: docState.zoomLevel, focus }, documentId);
+     }

pnpm-lock.yaml

@@ -30,6 +30,7 @@ patchedDependencies:
   '@embedpdf/core@2.15.0': 2000da4fd605dad67860a28724f4ab90eafa7215b89abe29df3f001bebc15a77
   '@embedpdf/engines@2.15.0': b4b3f0ea41ff20fd1f076c2b0a880f5b580a3ebdf5c69c95a7ee09a91183f924
   '@embedpdf/plugin-scroll@2.15.0': ef47017e5f4370e4c13ae1a5b523683acaaa68db36290094f8badab4614c6d0d
+  '@embedpdf/plugin-zoom@2.15.0': 39f7f5ddd05c0dadd63f5fc076e679140d1b0f8761a4899176076b563e361d77
 
 importers:
 
@@ -133,7 +134,7 @@ importers:
         version: 2.15.0(@embedpdf/core@2.15.0(patch_hash=2000da4fd605dad67860a28724f4ab90eafa7215b89abe29df3f001bebc15a77)(preact@10.29.7)(react-dom@19.2.7(react@19.2.7))(react@19.2.7)(svelte@5.56.4(@typescript-eslint/types@8.67.0))(vue@3.5.41(typescript@6.0.3)))(preact@10.29.7)(react-dom@19.2.7(react@19.2.7))(react@19.2.7)(svelte@5.56.4(@typescript-eslint/types@8.67.0))(vue@3.5.41(typescript@6.0.3))
       '@embedpdf/plugin-zoom':
         specifier: 2.15.0
-        version: 2.15.0(bae5492da052cd1ccfa4d859ce720d47)
+        version: 2.15.0(patch_hash=39f7f5ddd05c0dadd63f5fc076e679140d1b0f8761a4899176076b563e361d77)(bae5492da052cd1ccfa4d859ce720d47)
       '@fontsource-variable/fraunces':
         specifier: ^5.3.0
         version: 5.3.0
@@ -10542,7 +10543,7 @@ snapshots:
       svelte: 5.56.4(@typescript-eslint/types@8.67.0)
       vue: 3.5.41(typescript@6.0.3)
 
-  '@embedpdf/plugin-zoom@2.15.0(bae5492da052cd1ccfa4d859ce720d47)':
+  '@embedpdf/plugin-zoom@2.15.0(patch_hash=39f7f5ddd05c0dadd63f5fc076e679140d1b0f8761a4899176076b563e361d77)(bae5492da052cd1ccfa4d859ce720d47)':
     dependencies:
       '@embedpdf/core': 2.15.0(patch_hash=2000da4fd605dad67860a28724f4ab90eafa7215b89abe29df3f001bebc15a77)(preact@10.29.7)(react-dom@19.2.7(react@19.2.7))(react@19.2.7)(svelte@5.56.4(@typescript-eslint/types@8.67.0))(vue@3.5.41(typescript@6.0.3))
       '@embedpdf/models': 2.15.0

pnpm-workspace.yaml

@@ -54,6 +54,7 @@ patchedDependencies:
   "@embedpdf/core@2.15.0": patches/@embedpdf__core@2.15.0.patch
   "@embedpdf/engines@2.15.0": patches/@embedpdf__engines@2.15.0.patch
   "@embedpdf/plugin-scroll@2.15.0": patches/@embedpdf__plugin-scroll@2.15.0.patch
+  "@embedpdf/plugin-zoom@2.15.0": patches/@embedpdf__plugin-zoom@2.15.0.patch
 minimumReleaseAgeExclude:
   - "@tsconfig/node24@24.0.5"
   - "@vue/language-core@3.3.10"