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/log.html

@@ -30,6 +30,7 @@
       <div class="empty">loading log…</div>
     </article>
 
+    {% if paid %}
     <aside id="chat-sidebar" class="log-page__chat">
       <div class="chat-header">
         <span class="chat-title">Ask Cassandra</span>
@@ -49,7 +50,24 @@
         <button id="chat-send" type="submit">Send</button>
       </form>
     </aside>
+    {% else %}
+    <aside class="log-page__chat log-page__chat--locked">
+      <div class="chat-header">
+        <span class="chat-title">Ask Cassandra</span>
+        <span class="chat-hint">paid-tier feature</span>
+      </div>
+      <div class="chat-locked">
+        <p>
+          <strong>Follow-up chat is a paid feature.</strong>
+          Ask the model a question about any past log &mdash; it sees the
+          full day's context: the strategic log, live market readings, and
+          the last 24 hours of thesis-filtered headlines.
+        </p>
+        <a class="btn-primary" href="/pricing">See pricing</a>
+      </div>
+    </aside>
+    {% endif %}
   </div>
 </section>
-<script src="{{ url_for('static', path='/js/chat.js') }}" defer></script>
+{% if paid %}<script src="{{ url_for('static', path='/js/chat.js') }}" defer></script>{% endif %}
 {% endblock %}