Add authentication to dispute endpoints and improve test coverage infrastructure

- Add get_authenticated_address() helper to extract wallet address from X-Wallet-Address header or JWT token
- Add authentication to dispute filing, evidence submission, verification, voting, and arbitrator authorization endpoints
- Replace hardcoded zero addresses with authenticated addresses from request headers
- Add DEV_MODE fallback for development without authentication
- Add --mock flag to experimental resource

.gitea/workflows/python-tests.yml

@@ -84,7 +84,9 @@ jobs:
             -c /dev/null --rootdir "$PWD" --import-mode=importlib \
             --tb=short -q --timeout=30 \
             -o asyncio_mode=auto \
-            --cov=apps --cov=packages --cov=cli --cov-append
+            --cov=apps --cov=packages --cov=cli --cov-append \
+            --cov-report=term-missing --cov-report=html \
+            --cov-fail-under=50
 
       - name: Run app and package tests with coverage
         run: |