- Replace server interactivity with vanilla JS (forms.js) for Popover, Calendar, TimePicker, NumberInput, and Counter components
- Rewrite all Razor components to static SSR using data-* attributes for JS hooks
- Simplify InputBase.cs (remove EventCallback, EditContext, SetValueAsync)
- Remove AddInteractiveServerComponents/AddInteractiveServerRenderMode from Program.cs
- Update demo pages: remove @rendermode, replace EditForm with native form
- Add InteractivityGapTests.cs with 30 scoped E2E tests
- Update FormsTests.cs selectors for new static SSR structure
- Fix year picker navigation bug and date format mismatch in forms.js
- All 126 tests passing
