refactor: move topic logic to topic api

[maciejmajek]

Purpose

Move one-shot topic receive logic out of ROS2BaseConnector and into ROS2TopicAPI, giving ROS2TopicAPI full ownership of subscriber lifecycle for receive_message calls. This also activates the previously stored but never-used _destroy_subscribers flag.

Proposed Changes

ROS2TopicAPI (src/rai_core/rai/communication/ros2/api/topic.py):

• Added receive_message(topic, timeout_sec, msg_type, qos_profile, auto_qos_matching) method.
  • Creates an internal subscriber (tracked in the already-declared _subscriptions dict) backed by the existing _generic_callback, which caches raw messages in _last_msg.
  • Returns a cached message immediately if it is fresh enough (received within timeout_sec).
  • Otherwise polls _last_msg until a message arrives or the timeout expires, raising TimeoutError on failure.
  • When destroy_subscribers=True, destroys and removes the subscription immediately after the first message is received (flag defaults to False to avoid the rclpy executor crash described in [launch_pytest] publishing error: cannot use Destroyable because destruction was requested ros2/rclpy#1142).

ROS2BaseConnector (src/rai_core/rai/communication/ros2/connectors/base.py):

• Removed self.last_msg cache dict and _last_message_callback helper — both are now superseded by ROS2TopicAPI.
• receive_message is now a thin delegation: calls _topic_api.receive_message(...) then wraps the raw result with general_callback_preprocessor.
• Removed unused Dict from the typing import.

Issues

• Closes fix: get transform timeout precision issue, missing resource destructors #775

Testing

CI + Local

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.53%. Comparing base (f3a4598) to head (ae93608).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #785      +/-   ##
==========================================
+ Coverage   73.17%   74.53%   +1.35%     
==========================================
  Files          82       82              
  Lines        3579     3589      +10     
==========================================
+ Hits         2619     2675      +56     
+ Misses        960      914      -46     

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