refactor(ui): sharpen buttons + inputs to rounded (4px) for modern minimal SaaS look

V2 sharper radii system aligned with Stripe Dashboard / Linear / Vercel
aesthetic — the v1 rounded-lg (8px) on buttons still felt too soft.

New scale:
- Buttons (CTA, submit, ghost, secondary): rounded-lg → rounded (4px)
- Form inputs (text/email/password/select/textarea): rounded-md → rounded (4px)
- Checkboxes: rounded-sm (2px) added explicitly to consent + remember-me
- Cards (pricing, bento, content panels): rounded-xl → rounded-lg (8px)
- Small icon tiles (w-10 h-10 / w-12 h-12 grad-bg squares): rounded-md → rounded
- Pills, badges, avatars, status orbs: rounded-full (KEPT)
- Inline code in legal CSS: rounded (4px) (KEPT)
- Legal blockquote/pre/draft-callout border-radius: 8px → 4px

Files modified (24):
- templates/macros/{button,bento,pricing_card}.html
- templates/marketing/{landing,tarifs,fonctionnalites,conformite,contact}.html
- templates/auth/{check_email,forgot_password,magic_link_request,
  oauth_finish_signup,passkey_setup,reset_password,totp_setup,totp_verify,
  verify_success}.html
- templates/billing/{success,cancel}.html
- templates/legal/{_layout,index}.html
- templates/{register,login}.html
- tests/test_marketing_landing_template.py (assertions updated to match v2)

Verification:
- 18/18 legal page tests pass (tests/_run_legal_pages_windows.py)
- 58/58 marketing landing tests pass

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

templates/legal/_layout.html

@@ -99,7 +99,7 @@
     background-color: rgba(247, 249, 252, 0.6);
     padding: 0.75rem 1rem;
     margin: 1.25rem 0;
-    border-radius: 0 8px 8px 0;
+    border-radius: 0 4px 4px 0;
     font-style: italic;
     color: rgba(6, 13, 26, 0.75);
   }
@@ -113,7 +113,7 @@
   .legal-content pre {
     background-color: #f7f9fc;
     border: 1px solid #e6ebf2;
-    border-radius: 8px;
+    border-radius: 4px;
     padding: 1rem;
     overflow-x: auto;
     margin-bottom: 1.25rem;
@@ -137,7 +137,7 @@
     border-left: 4px solid #f59e0b;
     padding: 0.75rem 1rem;
     margin: 1rem 0 1.5rem;
-    border-radius: 0 8px 8px 0;
+    border-radius: 0 4px 4px 0;
     font-size: 0.9rem;
     color: #78350f;
   }
@@ -199,7 +199,7 @@
 {% block content %}
 {# Skip link (WCAG 2.4.1) — visible uniquement au focus clavier. #}
 <a href="#main-content"
-   class="sr-only focus:not-sr-only focus:fixed focus:top-2 focus:left-2 focus:z-[100] focus:px-4 focus:py-2 focus:bg-brand-navy focus:text-white focus:rounded-lg focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2">
+   class="sr-only focus:not-sr-only focus:fixed focus:top-2 focus:left-2 focus:z-[100] focus:px-4 focus:py-2 focus:bg-brand-navy focus:text-white focus:rounded focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2">
   Aller au contenu principal
 </a>
 
@@ -221,7 +221,7 @@
     <article id="main-content"
              role="main"
              aria-labelledby="legal-title"
-             class="bg-white p-6 md:p-10 rounded-xl border border-brand-border shadow-cta order-1">
+             class="bg-white p-6 md:p-10 rounded-lg border border-brand-border shadow-cta order-1">
       <header class="mb-8 pb-6 border-b border-brand-border">
         <p class="text-xs uppercase tracking-wider text-brand-navy/70 mb-2">Document légal DictIA</p>
         <h1 id="legal-title" class="text-3xl md:text-4xl font-black text-brand-navy mb-4 tracking-tight">{{ title }}</h1>
@@ -244,8 +244,8 @@
       </header>
 
       {# TOC mobile (collapsible) — visible < lg seulement #}
-      <details class="lg:hidden mb-6 border border-brand-border rounded-xl bg-brand-bg/50">
-        <summary class="cursor-pointer px-4 py-3 text-sm font-semibold text-brand-navy flex items-center justify-between focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2 rounded-xl">
+      <details class="lg:hidden mb-6 border border-brand-border rounded-lg bg-brand-bg/50">
+        <summary class="cursor-pointer px-4 py-3 text-sm font-semibold text-brand-navy flex items-center justify-between focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2 rounded-lg">
           <span>Sur cette page</span>
           <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
                stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
@@ -268,7 +268,7 @@
         {% if prev_page %}
         <a href="{{ url_for('legal.legal_page', page=prev_page) }}"
            rel="prev"
-           class="block p-4 bg-brand-bg/60 border border-brand-border rounded-xl hover:border-brand-b1 hover:bg-white transition focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2">
+           class="block p-4 bg-brand-bg/60 border border-brand-border rounded-lg hover:border-brand-b1 hover:bg-white transition focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2">
           <span class="block text-xs uppercase tracking-wider text-brand-navy/60 mb-1">
             <span aria-hidden="true">←</span> Précédent
           </span>
@@ -281,7 +281,7 @@
         {% if next_page %}
         <a href="{{ url_for('legal.legal_page', page=next_page) }}"
            rel="next"
-           class="block p-4 bg-brand-bg/60 border border-brand-border rounded-xl hover:border-brand-b1 hover:bg-white transition focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2 sm:text-right">
+           class="block p-4 bg-brand-bg/60 border border-brand-border rounded-lg hover:border-brand-b1 hover:bg-white transition focus-visible:outline-2 focus-visible:outline-brand-b1 focus-visible:outline-offset-2 sm:text-right">
           <span class="block text-xs uppercase tracking-wider text-brand-navy/60 mb-1">
             Suivant <span aria-hidden="true">→</span>
           </span>
@@ -304,7 +304,7 @@
            aria-label="Table des matières">
       <div x-data="legalToc()"
            x-init="init()"
-           class="legal-toc bg-white border border-brand-border rounded-xl p-5 mt-0">
+           class="legal-toc bg-white border border-brand-border rounded-lg p-5 mt-0">
         <h2 class="text-xs font-bold uppercase tracking-wider text-brand-navy/70 mb-3">
           Sur cette page
         </h2>