Canteen Management

Row actions: replaced the text "Edit" button + separate Archive icon button with a single ghost pencil icon button (prototype has no per-row delete/archive at all). Archive removed from the UI; the backend archive capability is untouched, just not surfaced here per the explicit ask to remove the delete option.

MenuItemDialog: title now "Edit item -- {name}" / "New menu item" (prototype format). Added an "Available today" toggle next to Vegetarian -- the create/update endpoint has no availability field of its own, so the dialog reconciles it with a second call to the existing SetAvailability endpoint only when the toggle disagrees with where the item already stands. Calories and HSN/SAC kept (not in the prototype modal, but real fields with no other place to set them) as their own row below the toggles, per the module owner's explicit call to keep them rather than drop the only way to set them.