Add: Unit tests for habit_bot and stock_tracker

- tests/test_habit_bot.py: Habit tracking, food logging, keto guidance
- tests/test_stock_tracker.py: Portfolio management, P&L calculation
- pytest.ini: Pytest configuration
- Updated Jenkinsfile: Emphasized testing stages before build

Pipeline stages:
1. Code Quality Gates (lint + security)
2. Unit Tests (pytest with coverage)
3. Integration Tests (Oracle, Telegram, Gitea)
4. Build (only after tests pass)
5. Deploy to Staging

pytest.ini

@@ -0,0 +1,20 @@
+[tool:pytest]
+testpaths = tests
+python_files = test_*.py
+python_classes = Test*
+python_functions = test_*
+addopts = 
+    -v
+    --tb=short
+    --strict-markers
+    --disable-warnings
+markers =
+    slow: marks tests as slow (deselect with '-m "not slow"')
+    integration: marks integration tests
+
+[tool:coverage:run]
+source = .
+omit = 
+    tests/*
+    venv/*
+    __pycache__/*