fix: update shadcn components and sidebar qa

[eirikhaugstulen]

What changed

• Updated the existing shadcn UI components with the latest CLI-generated component implementations and compatibility fixes.
• Fixed zod/react-resizable/import issues surfaced by the component update.
• Improved responsive layout behavior across dashboard, form field plugin, and enrollment overview screens.
• Added a localhost-only mockLongSidebar=true QA mode for enrollment plugin/widget sidebar stress testing.
• Made the enrollment add-widget sheet internally scrollable for long plugin/widget lists.
• Softened shared dialog/sheet/alert-dialog overlays from a heavy black backdrop to a lighter blurred backdrop.

Why

The shadcn refresh exposed a few app-shell and viewport issues. This PR keeps the generated components current while preserving DHIS2 app-shell compatibility and improves the enrollment configurator behavior under long sidebar content.

Validation

• yarn type-check
• yarn eslint src
• yarn build
• Browser QA on http://localhost:3000/ across desktop, mobile, and short-height viewports
• Verified long mocked enrollment sidebar can scroll to the bottom without horizontal overflow
• Verified softened overlay renders as rgba(0,0,0,0.3) with blur(4px)