Add tests + fix db.py SQLite commit pattern

Tests:
- tests/test_commands.py: parse_args, extract_args, format_bounty
- tests/test_db.py: full CRUD + tracking + reminders
- tests/conftest.py: temp DB fixture
- requirements-dev.txt: pytest + pytest-asyncio

db.py fixes:
- Explicit conn.commit() after every write (SQLite row_factory
  disables implicit transaction management)
- fetchone() before commit() (can't commit while cursor open)
- Functions return dict instead of sqlite3.Row

apps/telegram-bot/tests/__init__.py

@@ -0,0 +1 @@
+# tests package