### What problem does this PR solve?
Feat: Adjust the style of the delete button on the agent side #9869
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Hi team, @ZhenhangTung @KevinHuSh @cike8899
About #10384 , I've completed the UI optimization adjustments for the
Agent page according to our previous discussions and the design draft
sketches provided by @Naomi. The main modifications include:
1. Adjusted the style and content of placeholder-node.
2. Adjusted the location of the dropdown (to the right of the
placeholder-node) .
3. Adjusted the tooltip position spacing when the mouse hovers in the
dropdown menu.
4. Hides the thick scroll bar on the dropdown component.
5. Highlight the connection line when dragging to generate a
placeholder-node
<img width="1323" height="509" alt="Image"
src="https://github.com/user-attachments/assets/0d366f7f-477d-4c00-bb58-d5d58b3a745f"
/>
Please review the related code modifications when you have time. Let me
know if further adjustments are needed!
Thanks！
### Type of change
- [x] Other (please describe): UI Enhancement
---------
Co-authored-by: leonlai <leonlai@futurefab.ai>
### What problem does this PR solve?
Fix: Highlight the edges after running #9538
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: Replace color variables according to design draft #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Fix: Fixed the issue that the condition of deleting the classification
operator cannot be connected anymore #3221
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: Adjust the style of the agent canvas connection line #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: The delete button is displayed only when the cursor is hovered
over the connection line #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Constructing query parameter options for the Retrieval operator
#3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Enables the message operator form to reference the data defined by
the begin operator #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Render agent details #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
