feat: allow easy deletion of favorites

[eiseleMichael]

closes #2753

• adds an icon button to un-favorite a message without having to go back to the original message
• move set_step_favorite to base datalayer, so it can easily be overwritten for users that want to store them separately

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Summary by cubic

Let users remove a favorite directly from the Favorites picker, with instant UI updates and a data-layer flow to persist the change.

• New Features

  • Trash button in the Favorites list to unfavorite in place.
  • Optimistic toggling updates messages and favorites immediately via react-client.
  • Added “Remove favorite” translation key across locales.

• Refactors

  • Added a default set_step_favorite to the base data layer, still overridable.
  • Socket handler uses the data layer, resolves the step for favorite/unfavorite, normalizes timestamps, emits updates, and refreshes favorites.

^{Written for commit fe132b4. Summary will update on new commits.}

[cubic-dev-ai]

2 issues found across 25 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="backend/chainlit/data/base.py">

<violation number="1" location="backend/chainlit/data/base.py:117">
P2: set_step_favorite signature is missing the user_id parameter that callers pass, causing a runtime TypeError for data layers that rely on the base implementation and blocking per-user favorites overrides.</violation>
</file>

<file name="backend/chainlit/socket.py">

<violation number="1" location="backend/chainlit/socket.py:355">
P2: Unverified client payload can be persisted as a favorite when no matching server-side step is found, allowing arbitrary message data to be injected into stored favorites.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}