Project export UI

[khvn26]

Scope

• New component: ProjectExport.tsx in web/components/import-export/ (alongside existing FeatureExport.tsx).
• New RTK Query service: useProjectExport.ts in common/services/.
  • createProjectExport mutation.
  • getProjectExports query.
• New request/response types in common/types/requests.ts and responses.ts.
• Integrate into the existing Export tab on project settings page.
  • Add a toggle or sub-tab: "Environment Export" (existing) / "Project Export" (new).
• UI elements:
  • Checkbox for optional data: tags (on by default).
  • "Include identity overrides" toggle gated behind project_import_export_identity_overrides feature flag, enabled when the identity override import issue lands.
  • "Export Project" button.
  • Export list with status polling (reuse pattern from FeatureExport.tsx).
  • Download button for completed exports.

Acceptance criteria

• User can select optional data toggles and create a project export.
• Export list shows status (Processing / Success / Failed) with polling.
• Download works for completed exports.