Implement Visual Caching Indicators for Nodes #83
Description
Description: To make caching behavior more transparent, the UI needs to visually communicate the state of each node.
* UI Task: Modify the node component in Vue to display a distinct visual state (e.g., a colored border, an icon, or a different opacity) if its results are cached and will be used in the next run.
* Tooltip/Hover State: Add a tooltip that appears when a user hovers over the caching indicator. The tooltip should explain why the node is cached, for example: "Cached: Inputs and settings have not changed since the last run."