refactor(ui): V3 fully square buttons + inputs (rounded-none, brutalist/Swiss aesthetic)

V3 finalizes the radii pass to a fully brutalist/Swiss visual language:

- Buttons (CTAs, submit, secondary, ghost, OAuth provider tiles): rounded-none (0px)
- Form inputs (text/email/password/select/textarea/code-entry): rounded-none (0px)
- Checkboxes: rounded-none (0px) — was rounded-sm
- Small icon tiles (w-10 h-10 / w-12 h-12 grad-bg squares): rounded-none (0px)
- Inline code blocks (totp recovery <pre>, secret <code>): rounded-none (0px)
- Cards (pricing, bento, content panels, modals, prev/next nav): rounded (4px) — was rounded-lg
- Alert / flash boxes: rounded (4px) — was rounded-lg
- Pills, badges, status chips, ordres pros avatars, decorative cosmic orbs: rounded-full preserved
- Legal _layout.html inline <style> blockquote/pre/code/draft-callout: border-radius 0 — was 4px

Updated tests/test_marketing_landing_template.py assertions:
- bento icon assertion: "grad-bg rounded " -> "grad-bg rounded-none "
- pricing recommended frame: "rounded-lg" -> "rounded" (with strict trailing-char match to avoid rounded-none false positive)

Verification: 18/18 legal tests pass, 58/58 marketing landing tests pass, 5/5 root redirect tests pass. Two pre-existing failures in test_marketing_secondary_pages (SOC 2 hedge text + gitea.innova-ai.ca URL) are unrelated to this radii pass.

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-lg{% endif %}">
+<div class="relative {% if recommended %}grad-bg p-[1.5px] rounded{% 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-lg border border-brand-border h-full flex flex-col">
+  <div class="bg-white p-8 rounded 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>