Fix mypy CI failures and module path conflicts

✅ Address mypy static analysis issues:
- Add type ignore comment for yaml import in deepagent.py
- Add types-PyYAML dependency to requirements-dev.txt
- Add py.typed marker file for proper package typing
- Update CI workflow to use --explicit-package-bases flag

🔧 CI workflow improvements:
- Fix module name conflict between 'parsers' and 'src.parsers'
- Use explicit-package-bases to resolve mypy path mapping issues
- Ensure consistent mypy behavior between local and CI environments

✅ Verification completed:
- All 78 unit tests passing
- Ruff linting clean on src/ directory
- Ruff formatting verified

This resolves the mypy errors preventing CI from passing while maintaining all existing functionality.

Author: vinod0m

.github/workflows/python-test.yml

@@ -42,7 +42,7 @@ jobs:
           fail_ci_if_error: false
           token: ${{ secrets.CODECOV_TOKEN }}
       - name: Run mypy static analysis
-        run: mypy src/ --ignore-missing-imports --exclude "src/llm/router.py"
+        run: mypy src/ --ignore-missing-imports --exclude "src/llm/router.py" --explicit-package-bases
 
   tests:
     name: Run tests matrix

requirements-dev.txt

@@ -6,4 +6,5 @@ mypy==1.9.0
 ruff==0.4.2
 python-dotenv==1.0.1
 PyYAML==6.0.1
+types-PyYAML==6.0.12.20240917
 pre-commit==3.7.1

src/agents/deepagent.py

@@ -12,7 +12,7 @@
 from langchain.tools import BaseTool
 from langchain_community.chat_message_histories import ChatMessageHistory
 from langchain_core.runnables.history import RunnableWithMessageHistory
-import yaml
+import yaml  # type: ignore
 
 # LLM names declared as Any so mypy accepts fallback to None if imports fail
 GoogleGenerativeAI: Any