#6228 [enhancement]: Outline error nodes in red

[achuthanmukundan00]

Summary

This PR adds a red box shadow ("outline") to nodes that have missing required inputs or execution errors. Addresses issue #6228

Key Changes

1. Error State Tracking:

   • Added isErrorNode and fieldErrors to the InvocationNodeData type for tracking the overall error state of a node and specific errors for individual inputs.
   • Dynamically update fieldErrors and isErrorNode in the node's data when an input field becomes valid/invalid.

2. Visual Feedback for Error Nodes:

   • I added a red outline at first, but that disappeared when zoomed out, making this feature useless for large workflows.
     
     

   • Instead I opted to use a box shadow which remained visible even when zoomed out very far.

   
   

3. State Initialization:

   • Updated all places where invocation nodes are initialized (e.g., buildInvocationNode, graphToWorkflow) to include default values for isErrorNode and fieldErrors.
   • Modified test cases and mock nodes (e.g., validateWorkflow.test.ts) to account for the new fields.

4. Behavior:

   • Nodes with missing or invalid inputs are highlighted with a red shadow.
   • Once all required inputs are valid, the red shadow disappears automatically.

5. Testing:

   • Functionality was manually tested locally, no frontend tests are implemented in line with project conventions