[8710] Expert homepage - typing in the composer starts a new chat

[andypalmi]

Description

Alternative to #8869 for the team to compare.

On the team overview, while the conversation is folded away, sending from the composer or picking a prompt now starts a new chat instead of extending the previous one. "Continue your conversation" still reopens the previous thread, and sending from inside it continues that chat as before.

1. An expired session no longer locks the composer or the prompts on the overview, since sending from there starts a new chat anyway. A reply left hanging by the expired session is dropped first.
2. While a reply is still live, the composer and prompts stay locked so a pending answer is not lost. The placeholder reads "The Expert is still replying. Stop it to start a new chat", next to the Stop button.
3. In Insights mode the selected resources carry over to the new chat, as the selector is only reachable inside the open conversation.

Related Issue(s)

Relates to #8710

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production
• Link to Changelog Entry PR, or note why one is not needed.

Labels

• Includes a DB migration? -> add the area:migration label

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.47%. Comparing base (f9ce7f3) to head (c021bcf).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8873   +/-   ##
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  Coverage   78.47%   78.47%           
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  Files         474      474           
  Lines       25702    25702           
  Branches     6844     6844           
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  Hits        20170    20170           
  Misses       5532     5532           

Flag	Coverage Δ
backend	78.47% <ø> (ø)

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[cstns]

we really need to implement multi-chat support

[andypalmi]

Yes I agree