Fix Anthropic SDK initialization error (upgrade to v0.71.0)

Fix 'Client.__init__() got an unexpected keyword argument proxies' error
that occurred when manually triggering AI analysis from the dashboard.

Issue:
- Anthropic SDK v0.8.0 had compatibility issues with httpx client
- Error occurred when instantiating anthropic.Anthropic(api_key=key)
- Prevented manual analysis trigger from working in production

Solution:
- Upgraded anthropic package from 0.8.0 to 0.71.0
- Updated requirements.txt with new version
- All tests still passing (49 passed, 1 skipped)

The newer SDK version resolves the internal httpx proxy parameter issue
and provides better compatibility with the current Python environment.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

requirements.txt

@@ -2,7 +2,7 @@ Flask==3.0.0
 Flask-Login==0.6.3
 Flask-Limiter==3.5.0
 Flask-WTF==1.2.1
-anthropic==0.8.0
+anthropic==0.71.0
 clamd==1.0.2
 bcrypt==4.1.2
 PyYAML==6.0.1