Improved session ID handling

[jonathanlab]

There's a few things of note here:

• I bumped the claude agent SDK. since 0.2.32 you can now pass a sessionId during initialisation. This means we can determine the session UUID beforehand.
• This is better than needing to store a temporary UUID which we generate ourselves, followed by then needing to reassign it once the SDK returns it's own generated UUID.
• The agent service and agent package had some very confusing handling of the session IDs going on. This simplifies it further.
• For some reason we were falling back to taskRunId if we did not have a sessionId which is super bad