Add heuristic classification (#7050)

# Description of Changes

- Adds a non-AI heuristic classification engine that classifies
documents client-side in the browser when AI is disabled
- Classification is billed as a policy run via a fast, non-blocking
meter endpoint; a default Classification policy is seeded per team
- Enables the policy engine by default

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

.github/workflows/push-docker.yml

@@ -139,7 +139,6 @@ jobs:
           tags: |
             type=raw,value=${{ steps.versionNumber.outputs.versionNumber }},enable=${{ github.ref == 'refs/heads/master' || github.ref == 'refs/heads/V2-master' }}
             type=raw,value=latest,enable=${{ github.ref == 'refs/heads/master' || github.ref == 'refs/heads/V2-master' }}
-            type=raw,value=alpha,enable=${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/testMain' }}
 
       - name: Build and push Unified Dockerfile (latest variant)
         id: build-push-latest