fix: resolve f-string escaping issues in Python debugging

F-STRING ESCAPING FIX: Use string concatenation instead of f-strings

Issue:
- SyntaxError: unterminated f-string literal
- f-string escaping conflicts in exec() within YAML
- Complex nested quoting causing parsing errors

Solution:
- Replace f-strings with string concatenation
- Use str(e) instead of f"{e}"
- Simpler string handling in exec() blocks
- Maintain error reporting functionality

Changes:
- print("❌ src import failed: " + str(e))
- print("❌ aitbc import failed: " + str(e))
- Removes f-string complexity
- Preserves error message display

Expected results:
- No more SyntaxError with f-strings
- Import debugging should work
- Clear error messages for failed imports
- Workflow should proceed to pytest execution

This should resolve the f-string escaping conflicts and allow
the import debugging to complete successfully.

.gitea/workflows/python-tests.yml

@@ -128,8 +128,8 @@ jobs:
             
             # Test specific imports that are failing
             echo "Testing problematic imports..."
-            venv/bin/python -c "import sys; print('Testing src import...'); sys.path.insert(0, '/opt/gitea-runner/workspace/repo/apps/agent-protocols/src'); exec('try:\n    import message_protocol\n    print(\"✅ src.message_protocol import successful\")\nexcept Exception as e:\n    print(f\"❌ src import failed: {e}\n')"
-            venv/bin/python -c "import sys; print('Testing aitbc import...'); sys.path.insert(0, '/opt/gitea-runner/workspace/repo/apps/blockchain-node/src'); exec('try:\n    import aitbc_chain\n    print(\"✅ aitbc_chain import successful\")\nexcept Exception as e:\n    print(f\"❌ aitbc import failed: {e}\n')"
+            venv/bin/python -c "import sys; print('Testing src import...'); sys.path.insert(0, '/opt/gitea-runner/workspace/repo/apps/agent-protocols/src'); exec('try:\n    import message_protocol\n    print(\"✅ src.message_protocol import successful\")\nexcept Exception as e:\n    print(\"❌ src import failed: \" + str(e))')"
+            venv/bin/python -c "import sys; print('Testing aitbc import...'); sys.path.insert(0, '/opt/gitea-runner/workspace/repo/apps/blockchain-node/src'); exec('try:\n    import aitbc_chain\n    print(\"✅ aitbc_chain import successful\")\nexcept Exception as e:\n    print(\"❌ aitbc import failed: \" + str(e))')"
             
             echo "=== RUNNING PYTHON TESTS ==="
             echo "Attempting to run tests with comprehensive error handling..."