Add 'Add URL bitstream' feature to workspace items

[amadulhaxxani]

Introduce an "Add bitstream from URL" action for workspace items: add a conditional button and modal UI to input a file URL and optional name. Implement component support using ScriptDataService to call the file-downloader script, manage processing state, show success/error notifications, and navigate to the created process detail on success. Add related unit tests (scriptDataService stub, UI visibility, invocation params, success/failure flows) and update English and Czech i18n strings.

Problem description

Users could technically run the file-downloader script via the generic processes UI, but that flow is not contextual to workspace-item editing and is less discoverable for submitters.
Issue #28 requires an indirect, workspace-item-local UX similar to existing contextual script-trigger patterns in the app.

Analysis

• Implemented a workspace-item action with modal inputs:
  • required URL
  • optional bitstream name
  • filename placeholder hint (e.g. image.png) to communicate extension expectation
• Reused existing app architecture instead of introducing new backend/API logic:
  • script availability guard via scriptWithNameExistsAndCanExecute
  • script execution via ScriptDataService.invoke('file-downloader', ...)
  • standard process success/error notifications
  • navigation to process detail using existing route helper
• Added focused unit coverage for:
  • action visibility (available/unavailable script)
  • invocation payload mapping (-u, -w, optional -n)
  • success and failure handling paths
• Localization updated in both EN and CS for all new UI strings (including placeholder).

Validation

• yarn run test:headless --include='**workspaceitem-actions.component.spec.ts' ✅ PASS (13/13)
• yarn run lint --quiet ✅ PASS
• yarn run build:prod ✅ PASS (with pre-existing custom-theme unused-file warnings only)

Copilot review

• Requested review from Copilot

[Copilot]

Pull request overview

Adds a contextual “Add bitstream from URL” action to workspace-item actions, leveraging existing Processes/Script infrastructure (file-downloader) to make the feature discoverable during submission editing.

Changes:

• Adds a conditional workspace-item action button and modal to input a URL + optional bitstream name.
• Invokes the file-downloader script via ScriptDataService, shows success/error notifications, and navigates to the created process on success.
• Adds unit tests for visibility, invocation parameters, and success/failure flows; updates EN/CS i18n strings.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/assets/i18n/en.json5	Adds English UI strings for the new workspace-item action + modal.
src/assets/i18n/cs.json5	Adds Czech UI strings for the new workspace-item action + modal.
src/app/shared/mydspace-actions/workspaceitem/workspaceitem-actions.component.ts	Implements modal state + file-downloader script invocation and post-success navigation.
src/app/shared/mydspace-actions/workspaceitem/workspaceitem-actions.component.html	Adds the conditional action button and modal UI (URL + optional name, processing spinner).
src/app/shared/mydspace-actions/workspaceitem/workspaceitem-actions.component.spec.ts	Adds unit coverage for button visibility and invocation/success/failure behavior.