pricing: land £7/£70 paid tier and make behaviour match

Marketing + behaviour pass to get the site ready for Paddle approval.

Pricing page
- £7/month, £70/year headline (was "Coming soon").
- Bigger tier names (was 11px uppercase mono — looked like chips).
- Real CTAs (button base styles were only scoped to .hero__ctas).
- "Best value" badge + drop-shadow on the Paid card; full-width
  block CTAs that align across both cards.
- "Free vs Paid at a glance" comparison table beneath the cards.
- Compact "Invite a friend — both get 50% off for 3 months"
  callout with the detail explanation behind a <dialog> popup.

Tier copy + behaviour now consistent
- Free strategic-log refresh is every 6 hours, not hourly. New
  read-side filter on /api/log/{latest,by-date} restricts free
  users to logs at boundary hours (00/06/12/18 UTC); paid users
  still see the most recent.
- Follow-up chat is paid-only. /api/chat returns 402 for free;
  the chat sidebar on /log is replaced with a locked aside and
  chat.js no longer loads at all for free users.
- Dashboard meta lines + landing copy softened so they no longer
  promise hourly to everyone.

Future-proofing copy on public pages
- Dropped "free forever" wording (we may close the free tier).
- "Trading 212 CSV" became "broker CSV (Trading 212 today; more
  planned)" on pricing + landing; the actual import UIs stay
  T212-specific.

Terms
- Renamed Terms of Service -> Terms and Conditions (Paddle
  expectation), bumped last-updated to 2026-05-26.
- New §6 Refunds covering the 14-day cooling off, post-window
  cancellation, termination-by-us refunds, statutory rights, and
  how to request a refund.
- Renumbered §7-§14 and fixed the disclaimer link labels.

Tests
- 6 new tests in tests/test_chat_and_log_gates.py cover the
  chat 402 + the boundary-hour filter on both log endpoints.
- Full suite: 205 passed, 5 skipped, 0 failed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/templates/dashboard.html

@@ -61,7 +61,9 @@
 <section id="log-panel" class="panel">
   <div class="panel-header">
     <span class="title">Strategic Log</span>
-    <span class="meta">generated hourly @ :20 UTC</span>
+    <span class="meta">
+      {% if paid %}refreshed hourly @ :20 UTC{% else %}refreshed every 6 hours &middot; <a href="/pricing">hourly on Paid</a>{% endif %}
+    </span>
   </div>
   <div class="panel-body"
        hx-get="/api/log/latest?as=html"
@@ -74,7 +76,9 @@
 <section id="news-panel" class="panel">
   <div class="panel-header">
     <span class="title">Flash News</span>
-    <span class="meta">last 24h · ingest hourly @ :10 UTC</span>
+    <span class="meta">
+      {% if paid %}last 24h &middot; ingest hourly @ :10 UTC{% else %}last 6h &middot; <a href="/pricing">full 24h on Paid</a>{% endif %}
+    </span>
   </div>
   <div class="panel-body panel-body--scroll"
        hx-get="/api/news?as=html&limit=40"