refactor(ui): modernize button + input border radii (rounded-lg/md/xl, sharper SaaS aesthetic)

Aligns DictIA marketing/auth/legal/billing templates with modern SaaS visual
conventions (Linear, Vercel, Stripe Dashboard, Notion). Old radii (12-18px)
felt dated; new system uses 6-12px for tighter, more contemporary corners.

Border radius system:
- Buttons (CTA, submit, secondary): rounded-[0.75rem] (12px) -> rounded-lg (8px)
- Form inputs (text/email/password/select/textarea/checkbox): rounded-[0.5rem] -> rounded-md (6px)
- Cards (pricing, bento, modals, content panels): rounded-[18px]/[14px]/[12px] -> rounded-xl (12px)
- Pricing card outer gradient frame: rounded-[20px] -> rounded-xl (matches inner)
- Pills / badges / status chips: KEEP rounded-full
- Avatars / circular icon containers: KEEP rounded-full
- Code blocks: KEEP rounded (4px)

Decision tree applied for ambiguous cases:
- Button-like clickable CTA -> rounded-lg
- Form input -> rounded-md
- Card / panel / modal -> rounded-xl
- Badge / pill / chip / avatar -> rounded-full (preserved)

In-scope templates modified (23):
- macros/button.html (central macro, cascades to all callers)
- macros/pricing_card.html, macros/bento.html
- marketing/landing.html, tarifs.html, fonctionnalites.html, conformite.html, contact.html
- auth/check_email.html, forgot_password.html, magic_link_request.html, oauth_finish_signup.html,
  passkey_setup.html, reset_password.html, totp_setup.html, totp_verify.html, verify_success.html
- billing/cancel.html, billing/success.html
- legal/_layout.html, legal/index.html
- register.html, login.html

Out of scope (untouched): index.html, account.html, admin.html, share.html, inquire.html,
group-admin.html, components/**, includes/**, modals/** (all legacy Speakr Vue surfaces).

Tests: test_marketing_landing_template.py — 2 assertions updated to match new bento icon
(rounded-md) and pricing card frame (rounded-xl). All 18 legal tests + 58 marketing landing
tests + 9 signup_loi25 tests still pass. Decorative rounded-full preserved on hero cosmic
orbs and ordres-pros avatar circles.

Diff: 94 insertions / 94 deletions (1:1 mechanical replacement, no class drift).

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

templates/macros/bento.html

@@ -3,10 +3,10 @@
    so dynamic `col-span-{{ span }}` would produce dead classes — the lookup keeps the utilities discoverable). #}
 {% macro bento_card(number, title, description, icon='✦', span='1') %}
 {%- set span_classes = {'1': 'col-span-1', '2': 'sm:col-span-2', '3': 'sm:col-span-2 md:col-span-3'} -%}
-<div class="relative bg-brand-navy2 p-6 rounded-[18px] overflow-hidden border border-white/[0.045] {{ span_classes.get(span, 'col-span-1') }}">
+<div class="relative bg-brand-navy2 p-6 rounded-xl overflow-hidden border border-white/[0.045] {{ span_classes.get(span, 'col-span-1') }}">
   <div class="absolute top-2 right-4 text-[80px] font-black text-white/[0.04]" aria-hidden="true">{{ number }}</div>
   <div class="relative">
-    <div class="w-10 h-10 grad-bg rounded-[0.5rem] mb-4 flex items-center justify-center text-lg">{{ icon }}</div>
+    <div class="w-10 h-10 grad-bg rounded-md mb-4 flex items-center justify-center text-lg">{{ icon }}</div>
     <h3 class="text-lg font-bold mb-2 text-white">{{ title | safe }}</h3>
     <p class="text-sm text-white/70">{{ description | safe }}</p>
   </div>

templates/macros/button.html

@@ -14,13 +14,13 @@
 {%- set sizing = sizes.get(size, sizes['md']) -%}
 {%- if as_button -%}
 <button type="{{ type }}"
-        class="inline-flex items-center justify-center gap-2 rounded-[0.75rem] font-semibold transition-all duration-200 {{ classes }} {{ sizing }}">
+        class="inline-flex items-center justify-center gap-2 rounded-lg font-semibold transition-all duration-200 {{ classes }} {{ sizing }}">
   <span>{{ text }}</span>
   {%- if icon -%}<span class="ml-0.5" aria-hidden="true">{{ icon | safe }}</span>{%- endif -%}
 </button>
 {%- else -%}
 <a href="{{ href }}"
-   class="inline-flex items-center justify-center gap-2 rounded-[0.75rem] font-semibold transition-all duration-200 {{ classes }} {{ sizing }}"
+   class="inline-flex items-center justify-center gap-2 rounded-lg font-semibold transition-all duration-200 {{ classes }} {{ sizing }}"
    {% if target %}target="{{ target }}"{% endif %}
    {% if rel %}rel="{{ rel }}"{% endif %}>
   <span>{{ text }}</span>

templates/macros/pricing_card.html

@@ -15,9 +15,9 @@
    The button macro autoescapes its `text` arg, so `name` MUST NOT contain HTML entities
    (verified: "DictIA 8", "DictIA 16", "DictIA Cloud" are all entity-free). #}
 {%- macro pricing_card(slug, name, price_setup, price_monthly, target, features, recommended=False, cta_url='/checkout') -%}
-<div class="relative {% if recommended %}grad-bg p-[1.5px] rounded-[20px]{% endif %}">
+<div class="relative {% if recommended %}grad-bg p-[1.5px] rounded-xl{% endif %}">
   {% if recommended %}<span class="absolute -top-3 left-1/2 -translate-x-1/2 grad-bg text-white text-xs font-bold px-3 py-1 rounded-full shadow-cta">★ RECOMMANDÉ</span>{% endif %}
-  <div class="bg-white p-8 rounded-[18px] border border-brand-border h-full flex flex-col">
+  <div class="bg-white p-8 rounded-xl border border-brand-border h-full flex flex-col">
     <div class="mb-6">
       <h3 class="text-xl font-black mb-1 text-brand-navy">{{ name | safe }}</h3>
       <p class="text-sm text-brand-navy/70">{{ target | safe }}</p>