Type UAV vehicle state

[ethayu]

Summary

• add explicit guards for nullable UAV GPS/local/yaw state before use
• type payload runtime node extensions with a structural protocol
• narrow dynamic vision node name/service helpers before calling them

Fixes #230
Part of #201

Verification

• source /opt/ros/humble/setup.bash && source /home/ubuntu/monorepo/controls/sae_2025_ws/install/setup.bash && export PYTHONPATH="$PWD/controls/sae_2025_ws/src/uav:$PYTHONPATH" && npx --yes pyright controls/sae_2025_ws/src/uav/uav/vehicles/UAV.py controls/sae_2025_ws/src/uav/uav/vehicles/Payload.py controls/sae_2025_ws/src/uav/uav/vehicles/Vehicle.py --outputjson
• python3 -m compileall controls/sae_2025_ws/src/uav/uav/vehicles/UAV.py controls/sae_2025_ws/src/uav/uav/vehicles/Payload.py controls/sae_2025_ws/src/uav/uav/vehicles/Vehicle.py
• ruff check --config controls/sae_2025_ws/.ruff.toml controls/sae_2025_ws/src/uav/uav/vehicles/UAV.py controls/sae_2025_ws/src/uav/uav/vehicles/Payload.py controls/sae_2025_ws/src/uav/uav/vehicles/Vehicle.py
• ruff format --check --config controls/sae_2025_ws/.ruff.toml controls/sae_2025_ws/src/uav/uav/vehicles/UAV.py controls/sae_2025_ws/src/uav/uav/vehicles/Payload.py controls/sae_2025_ws/src/uav/uav/vehicles/Vehicle.py
• python3 -m pytest -q controls/sae_2025_ws/src/uav/test/test_runtime_behavior.py controls/sae_2025_ws/src/uav/test/test_peer_runtime_contract.py