feat(backend): Add ClamAV support for anti-virus scan on file upload to the platform (#10232)

An anti-virus file scan step is added to each file upload step on the
platform before the file is sent to cloud storage or local machine
storage.

### Changes 🏗️

* Added ClamAV service
* Added AV file scan on each upload step
* Added tests & documentation
* Make the step mandatory even on local development

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  <!-- Put your test plan here: -->
  - [x] Tried using FileUploadBlock & AgentFileInputBlock

autogpt_platform/CLAUDE.md

@@ -19,7 +19,7 @@ cd backend && poetry install
 # Run database migrations
 poetry run prisma migrate dev
 
-# Start all services (database, redis, rabbitmq)
+# Start all services (database, redis, rabbitmq, clamav)
 docker compose up -d
 
 # Run the backend server
@@ -92,6 +92,7 @@ npm run type-check
 2. **Blocks**: Reusable components in `/backend/blocks/` that perform specific tasks
 3. **Integrations**: OAuth and API connections stored per user
 4. **Store**: Marketplace for sharing agent templates
+5. **Virus Scanning**: ClamAV integration for file upload security
 
 ### Testing Approach
 - Backend uses pytest with snapshot testing for API responses