Remove azuldownload and curldownload feature flags

[frano-m]

Summary

• Remove AZUL_DOWNLOAD and CURL_DOWNLOAD feature flags so download features are enabled unconditionally
• Delete wrapper components (AzulFileDownloadVisibilityController, CurlDownloadExportMethod) that existed solely for feature gating
• Preserve NRES consent group check for curl download (business logic, not a feature gate)

Closes #4733

Test plan

• Verify file download column is visible by default on AnVIL files tab
• Verify curl download export method appears on cohort and dataset export pages without needing ?curldownload flag
• Verify curl download is still restricted to NRES datasets
• Verify NCPI export feature flag still works independently

🤖 Generated with Claude Code

Closes #4733.

[Copilot]

Pull request overview

Removes the AZUL_DOWNLOAD and CURL_DOWNLOAD feature flags so Azul file download and curl download functionality are enabled by default, while keeping the NRES consent-group restriction for dataset curl downloads.

Changes:

• Deleted the Azul/curl download feature flags and removed their gating logic/components.
• Made the Azul file download column visible by default (removed feature-flag-driven visibility controller and default-hidden state).
• Kept curl download restricted to NRES datasets via existing consent-group checks/conditional rendering.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
site-config/anvil-cmg/dev/ui/filesEntityList.ts	Removes the now-unnecessary Azul download visibility controller slot.
site-config/anvil-cmg/dev/index/filesEntityConfig.ts	Stops default-hiding the Azul file download column so it appears by default.
site-config/anvil-cmg/dev/export/export.ts	Replaces the curl download gated export method wrapper with the standard ExportMethod.
site-config/anvil-cmg/dev/detail/dataset/export/export.ts	Replaces the curl download gated export method wrapper with the standard ExportMethod (still wrapped by NRES conditional).
pages/export/get-curl-command.tsx	Removes feature-flag-based 404 gating so the page is always available.
pages/[entityListType]/[...params].tsx	Removes curl feature-flag check while preserving NRES-based restriction for AnVIL dataset curl routes.
app/shared/entities.ts	Removes AZUL_DOWNLOAD and CURL_DOWNLOAD from the FEATURES enum.
app/components/index.tsx	Removes the Azul download “visibility controller” export alias.
app/components/Index/components/AzulFileDownload/azulFileDownload.tsx	Deletes the feature-flag-based column visibility controller component.
app/components/Export/components/AnVILExplorer/CurlDownload/curlDownloadExportMethod.tsx	Deletes the feature-flag-based curl export method wrapper component.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.