React 19 Upgrade

[jwinters01]

Upgrades Repo to React-19

Notable changes

There's a lot of changes in this PR, some of them are just

react-form Compatibility Layer (src/components/form/compat.tsx) — New file

The react-form package (which used class-based internals incompatible with React 19) was removed and replaced with a custom hooks-based implementation that preserves the same public API surface.

Implements the following:

• component with defaultValues, validateError, onSubmit, and getApi callbacks — matching the old react-form API
• FormApi object with values, errors, touched, setValue, setError, submitForm, getFormState, setAllValues, setFormState
• FormField HOC (withFieldApi) that connects any component to the form via React context
• Built-in field components: Text, TextArea, Checkbox
• Supports both context-based and prop-based (formApi prop) form API injection
• Uses Proxy-like getter/setter pattern on the FormApi object so that mutations to api.values, api.errors, api.touched trigger re-renders (important for callers that mutate rather than call setters)
• Exported both as ReactForm.* namespace and as named exports for drop-in compatibility

Autocomplete Re-implementation (src/components/autocomplete/autocomplete.tsx)

Replaced the deprecated react-autocomplete library with a custom implementation built on downshift's useCombobox hook:

• Full re-write from class-based ReactAutocomplete to a functional hooks-based component
• Menu positioning logic (including flip-to-top when near viewport edge) is now owned directly in the component rather than monkey-patched onto the old library's class instance
• Listens to both scroll and resize events for dynamic repositioning
• Preserves the public AutocompleteProps API (filterSuggestions, autoHighlight, renderItem, renderInput, autoCompleteRef, onSelect, onChange, etc.)

Exports (src/components/index.ts)

All compatibility layer types and components are re-exported from the package's main entry point, allowing argo-cd to import from argo-ui without changes.

Enzyme Sunset

Enzyme is no longer supported for React 19, it needed to be removed.

Other Changes

• Package dependencies updated (React 19, Storybook upgrades, downshift added, react-autocomplete/react-form removed)
• Test files migrated from .spec.tsx → .test.tsx convention
• Minor React 19 compatibility fixes across various components (ref handling, prop changes)