Fix: Save button now disables after Ctrl+S in NodeDetailsModal

Added internal state tracking to properly detect changes after save:
- Added savedNode state to track baseline independently of parent prop
- Update both editedNode and savedNode after successful mutation
- Compare editedNode with savedNode instead of stale node prop
- Added awaitRefetchQueries to ensure mutation completes before state update
- Added keyboard shortcuts (ESC to close, Ctrl+S to save)
- Integrated with dialog manager for proper cleanup

This fixes the issue where the Save button remained enabled after
pressing Ctrl+S because the parent component's node prop wasn't
updating after the GraphQL refetch.

Author: Patel230