refactor(api): Separate SegmentType for Integer/Float to Enable Pydantic Serialization (#22025)

refactor(api): Separate SegmentType for Integer/Float to Enable Pydantic Serialization (#22025)

This PR addresses serialization issues in the VariablePool model by separating the `value_type` tags for `IntegerSegment`/`FloatSegment` and `IntegerVariable`/`FloatVariable`. Previously, both Integer and Float types shared the same `SegmentType.NUMBER` tag, causing conflicts during serialization.

Key changes:
- Introduce distinct `value_type` tags for Integer and Float segments/variables
- Add `VariableUnion` and `SegmentUnion` types for proper type discrimination
- Leverage Pydantic's discriminated union feature for seamless serialization/deserialization
- Enable accurate serialization of data structures containing these types

Closes #22024.

web/app/components/workflow/nodes/agent/components/tool-icon.tsx

@@ -61,7 +61,7 @@ export const ToolIcon = memo(({ providerName }: ToolIconProps) => {
   >
     <div
       className={classNames(
-        'size-5 border-[0.5px] border-components-panel-border-subtle bg-background-default-dodge relative flex items-center justify-center rounded-[6px]',
+        'relative flex size-5 items-center justify-center rounded-[6px] border-[0.5px] border-components-panel-border-subtle bg-background-default-dodge',
       )}
       ref={containerRef}
     >
@@ -73,7 +73,7 @@ export const ToolIcon = memo(({ providerName }: ToolIconProps) => {
             src={icon}
             alt='tool icon'
             className={classNames(
-              'w-full h-full size-3.5 object-cover',
+              'size-3.5 h-full w-full object-cover',
               notSuccess && 'opacity-50',
             )}
             onError={() => setIconFetchError(true)}
@@ -82,7 +82,7 @@ export const ToolIcon = memo(({ providerName }: ToolIconProps) => {
         if (typeof icon === 'object') {
           return <AppIcon
             className={classNames(
-              'w-full h-full size-3.5 object-cover',
+              'size-3.5 h-full w-full object-cover',
               notSuccess && 'opacity-50',
             )}
             icon={icon?.content}