Refactoring and save manifest metadata as fields / not file

[scolapasta]

This PR refactors the code base:
• clean up db structure
• merges version and manifest class objects so that the manifest metadata is (effectively 1-1) with the version
• stores manifest metadata as individual fields, not as a file
• allows for multiple content types, then creates individual manifests for downloads
• adds several cancel buttons in the UI

• adds delete tool

Closes #16
Closes #30

[Copilot]

Pull Request Overview

This PR refactors how manifest metadata is stored and managed, consolidating version and manifest models, and replacing file-based uploads with structured form fields. It also enhances dynamic input handling, image state management, and UI theme persistence.

• Store manifest metadata as individual fields and merge with version object
• Introduce MultiInputGroup for dynamic list inputs and new EditManifestForm modal
• Update image and tool creation forms to handle state immutably and integrate manifest data
• Add theme switcher enhancements and new MarketplaceLinkCard variant

Reviewed Changes

Copilot reviewed 111 out of 111 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
useEditManifestForm.tsx	New hook to manage manifest form state and JSON uploads
MultiInputGroup.tsx	Component to add/remove dynamic string, keyValue, and object arrays
EditVersionForm.tsx & EditVersionCard.tsx	Replace manifest file inputs with structured edit modal
useEditImageForm.ts	Fix image list state handling
EditImageForm.tsx	Update image upload UI to use state array from hook
useAddExternalTool.ts & AddExtToolForm.tsx	Integrate manifest modal into add tool flow and build multipart form
UserContextProvider.tsx, useThemeSwitcher.ts, ThemeSwitcher.tsx	Persist theme choice in context and local storage
MarketplaceCard.tsx	Add MarketplaceLinkCard variant and style updates
FormInputFields.tsx	Consolidate form input components and nested change handler

Comments suppressed due to low confidence (2)

dv-marketplace/src/components/forms/AddExternalToolForm/useAddExternalTool.ts:30

• The field versioneNote appears to be a typo; rename to versionNote for consistency with other form fields.

versioneNote: form.versioneNote.value,

dv-marketplace/src/components/UI/MarketplaceCard.tsx:14

• Missing import of Link from react-router-dom; add import { Link } from 'react-router-dom'; at the top.

export const MarketplaceLinkCard = ({ header, imageId, text, link, children }: CardDeckProps) => {

[Copilot]

Avoid directly mutating the images array; use setImages(prev => [...prev, item]) to update state immutably so React re-renders correctly.

[Copilot]

[nitpick] Hardcoding BASE_URL reduces flexibility; consider injecting it via environment variables or using a shared API hook.

Suggested change

	const BASE_URL = 'http://localhost:8081';
	const BASE_URL = process.env.REACT_APP_BASE_URL || 'http://localhost:8081';

[Copilot]

[nitpick] Using index as a React key can lead to rendering issues; if possible, provide a stable unique identifier for each item instead.

Suggested change

	<Form.Group key={index} controlId={`${namePrefix}-${index}`}>
	<Form.Group key={uniqueKey} controlId={`${namePrefix}-${index}`}>