feat: Edit + Copy Chat Prompt with Versioning (#1231) (#1636)

[princeaden1]

Edit Prompt and Copy Prompt functionality with full version tracking. When a user edits a message, a new version is created while the previous version is hidden. Users can navigate between versions using the version controls.

Key Changes

• Added edit prompt flow with versioned message creation
• Implemented copy prompt action
• Ensured edited messages generate new version entries without modifying the original
• Added UI logic for showing/hiding versions

Next Steps
Finalize E2E tests (to be completed in a follow-up PR)

Closes
(#1231) (#1636)

[cubic-dev-ai]

2 issues found across 12 files

Prompt for AI agents (all 2 issues)

Understand the root cause of the following 2 issues and fix them.


<file name="src/components/chat/MessagesList.tsx">

<violation number="1" location="src/components/chat/MessagesList.tsx:92">
Guard the activeVersionsState entries (or reset them per chat) so that stale IDs from a different conversation cannot make visibleMessages empty when the selected message no longer exists.</violation>

<violation number="2" location="src/components/chat/MessagesList.tsx:165">
Use a stable identifier such as message.id as the key so React can correctly mount/unmount ChatMessage when the visible version changes.</violation>
</file>

_{Reply to cubic to teach it or ask questions. Re-run a review with @cubic-dev-ai review this PR}

[wwwillchen]

i think this is an interesting idea, but there's a lot of weird edge cases right now:

• this PR breaks existing user chat messages - it doesn't render old user chat messages.
• if you go to an earlier message, and then send a new message. the new message is added under the latest message, which is a confusing UX
• if you edit a message, it doesn't undo the previous change.

if you look at what editors like Cursor do, I think their editing experience is more intuitive (and simpler).

• if you edit, it effectively does a restore version to the state before that user message.
• you can't cycle between the old and new versions.

i think chatgpt's UX makes sense b/c it's a pure chat environment but it gets very confusing once you deal with code.

wdyt?

[princeaden1]

@wwwillchen You're totally right, thanks for calling out those cases. I'm reworking the code now to align with your suggestion. I initially thought we could lean more toward the ChatGPT-style flow, but as you mentioned, that UX fits pure chat much better than an agentic/code-editing context.

I'll update the PR this week to reflect this direction.