Fix the dedup workflow so it actually works (#41580)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request
Had some bad syntax in the first iteration, tested this on my fork and
it adds the "duplicate" label and comments which issues it's a dup of.
<img width="952" height="333" alt="image"
src="https://github.com/user-attachments/assets/71645d79-5fa0-4c66-a560-32a033d14dc9"
/>


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## PR Checklist

- [ ] Closes: #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

.github/actions/spell-check/expect.txt

@@ -330,6 +330,7 @@ Deact
 debugbreak
 decryptor
 Dedup
+Deduplicator
 Deeplink
 DEFAULTBOOTSTRAPPERINSTALLFOLDER
 DEFAULTCOLOR

.github/workflows/manual-batch-issue-deduplication.yml

@@ -1,20 +1,38 @@
 name: Manual Batch Issue Deduplication
 
 on:
-  workflow_dispatch: # Only runs when manually triggered
+  workflow_dispatch:
+    inputs:
+      issue_numbers:
+        description: "JSON array of issue numbers to deduplicate (e.g. [101,102,103])"
+        required: true
+      since:
+        description: "Only compare against issues created after this date (ISO 8601, e.g. 2019-05-05T00:00:00Z)"
+        required: false
+        default: "2019-05-05T00:00:00Z"
+      label_as_duplicate:
+        description: "Apply duplicate label if duplicates are found (true/false)"
+        required: false
+        default: "true"
+
+permissions:
+  models: read
+  issues: write
 
 jobs:
-  batch-deduplicate:
+  deduplicate:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        issue: ${{ fromJson(github.event.inputs.issue_numbers) }}
     steps:
-      - name: Batch Deduplicate Issues
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Run GenAI Issue Deduplicator
         uses: pelikhan/action-genai-issue-dedup@v0
         with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          label-duplicate: "potential duplicate"
-          comment-duplicate: true
-          close-duplicate: false
-          batch-size: 100 
-          since: '2019-05-05T00:00:00Z' # Process issues dating back to 2019
-          duplicate-comment-template: "This issue appears to be a duplicate of #{duplicate_issue_number}."
-          # Add other action-specific inputs if needed
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          github_issue: ${{ matrix.issue }}
+          label_as_duplicate: ${{ github.event.inputs.label_as_duplicate }}
+