Everything on the shared names — the copy-paste is gone

The ported markup was written a page at a time, so the same thing was said several ways. Counted before
touching anything: nine variants of the page gutter, seven max-widths, six link styles, two definitions of
an input, and one stray shadow.

Now: `container` (which already centres and pads), `measure`/`measure-wide`, `link`/`link-plain`/
`link-on-dark`, one `field`, `photo`, `page-head`. Nothing in a template writes `bg-white rounded-…
shadow-…` or `underline underline-offset-4` any more — 119 uses of `panel`, 82 of `label`, 52 of
`panel-lift`, 17 of `link`.

TWO REAL FIXES FELL OUT OF IT, not just tidying:

- Every section said `container mx-auto px-4`: `mx-auto` twice, and a px-4 that beat the responsive
  padding inside `container`. The gutter was 16px at every width, including on a 27-inch screen. Removing
  the copy-paste restores sm:px-6 lg:px-8, which is most of why the pages now breathe.
- The public form and the admin had grown two different inputs — cream vs white, ring-2 vs ring-1, py-2.5
  vs py-2, and different text sizes. There is one `field` now, and the same focus ring as everything else.

The admin uses the same names where they are the same thing (`link`, `field`, `h4`, `--radius-*`) and
keeps its own denser buttons, because it is a tool and not a shop front.

53 tests green. Every class used across all nine pages resolves in the compiled stylesheet — that check is
what makes a sweep this size safe to do with a script.

src/main/resources/templates/fragments/header.html

@@ -17,7 +17,7 @@
   here would resolve against the 80px header box and get clipped to a sliver.
 */-->
 <header th:fragment="header" class="sticky top-0 z-40 bg-bakery-50/90 backdrop-blur border-b border-bakery-200">
-  <div class="container mx-auto px-4">
+  <div class="container">
     <div class="flex items-center justify-between gap-2 h-20 md:h-24">
       <div th:replace="~{fragments/lockup :: small('text-bakery-700')}"></div>
 
@@ -37,7 +37,7 @@
           </svg>
         </summary>
         <div class="absolute inset-x-0 top-full z-30 h-[calc(100dvh-5rem)] bg-bakery-50">
-          <nav class="container mx-auto px-4 flex flex-col">
+          <nav class="container flex flex-col">
             <th:block th:replace="~{:: links('text-bakery-800 hover:text-bakery-600 transition py-4 text-lg border-b border-bakery-100')}"></th:block>
           </nav>
         </div>