Related to #28490.
- Default prompts from the prompt library are now included as "user
rules" in the system prompt.
- Presence of these user rules is shown at the beginning of the thread
in the UI.
_ Now uses an `Entity<PromptStore>` instead of an `Arc<PromptStore>`.
Motivation for this is emitting a `PromptsUpdatedEvent`.
- Now disallows concurrent reloading of the system prompt. Before this
change it was possible for reloads to race.
Release Notes:
- agent: Added support for including default prompts from the Prompt
Library as "user rules" in the system prompt.
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Co-authored-by: Danilo Leal <daniloleal09@gmail.com>