feat(picviewer): add local QR code scanner

.github/workflows/apply-picviewer-qr.yml

@@ -0,0 +1,57 @@
+name: Apply Picviewer QR patch
+
+on:
+  push:
+    branches:
+      - feature/picviewer-qr-scan
+    paths:
+      - "Picviewer CE+/tools/apply-qr-patch.js"
+      - ".github/workflows/apply-picviewer-qr.yml"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  patch-and-verify:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out feature branch
+        uses: actions/checkout@v4
+        with:
+          ref: feature/picviewer-qr-scan
+          fetch-depth: 0
+
+      - name: Apply QR integration
+        run: node "Picviewer CE+/tools/apply-qr-patch.js"
+
+      - name: Verify JavaScript syntax
+        run: node --check "Picviewer CE+/Picviewer CE+.user.js"
+
+      - name: Verify patch markers
+        shell: bash
+        run: |
+          set -euo pipefail
+          file="Picviewer CE+/Picviewer CE+.user.js"
+          grep -Fq "// @resource             jsQR https://cdn.jsdelivr.net/npm/jsqr@1.4.0/dist/jsQR.js" "$file"
+          grep -Fq "// Picviewer QR integration start" "$file"
+          grep -Fq "case 'qr':" "$file"
+          grep -Fq "pv-float-bar-button-qr" "$file"
+          grep -Fq "actual,current,qr,gallery,magnifier,download,stitch" "$file"
+          test "$(grep -Fc "// Picviewer QR integration start" "$file")" -eq 1
+
+      - name: Verify clean diff
+        run: git diff --check
+
+      - name: Commit generated integration
+        shell: bash
+        run: |
+          if git diff --quiet; then
+            echo "QR integration is already up to date."
+            exit 0
+          fi
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git add "Picviewer CE+/Picviewer CE+.user.js"
+          git commit -m "feat(picviewer): add QR code scanner"
+          git push origin HEAD:feature/picviewer-qr-scan