Add shopper accounts, reviews, tracking, and seed_demo (#10)

## Summary
- Closes #9. Port shop-gated buyer accounts (register/login/profile, password reset, order history), purchase-gated reviews, and Stripe customer ids. Cards stay on Stripe.
- Slim public contact form to email + interest + message. Shipping tracking status, scan events, paste-in numbers, and EasyPost webhook when FEATURE_SHIPPING is on.
- Add template-neutral `seed_demo` (generic SKUs, demo shoppers, guest orders, tracking stubs). Prod refused. `--reset` deletes tagged demo rows after invoices.

## Test plan
- [ ] `cd site && uv run python manage.py test` (173 tests passed locally)
- [ ] Shop on: `/account/register`, login, profile, password reset, claim guest orders by email
- [ ] Shop off: `/account/` URLs absent; Sign in / Account links hidden
- [ ] Checkout as logged-in buyer stores `Order.user` and Stripe customer id; product review only after paid purchase
- [ ] Shipping on: portal paste-in tracking + EasyPost webhook updates status; shipping off: orders still work without tracking UI
- [ ] `seed_demo` refused in prod; `--reset` rebuilds tagged catalog/shoppers without deleting staff invoices

Reviewed-on: #10

site/accounts/templates/accounts/profile.html

@@ -0,0 +1,84 @@
+{% extends "accounts/account_base.html" %}
+{% load static %}
+{% block title %}Profile · {{ SITE_NAME }}{% endblock %}
+{% block extra_head %}
+<link rel="stylesheet" href="{% static 'css/address-autocomplete.css' %}">
+{% endblock %}
+{% block account_content %}
+          <h3>Profile &amp; shipping</h3>
+          <p>Name, phone, and a default shipping address. Payment cards stay on Stripe — we only keep a Stripe customer id, never card numbers.</p>
+          {% if profile.stripe_customer_id %}
+          <p class="text-gray-600">Stripe customer on file. Saved cards are offered at checkout by Stripe.</p>
+          {% endif %}
+          <form class="rd-form" method="post">
+            {% csrf_token %}
+            {{ form.non_field_errors }}
+            <div class="row row-20 gutter-20" data-address-autocomplete data-suggest-url="{% url 'address_suggest' %}">
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.first_name.id_for_label }}">First name</label>
+                  {{ form.first_name }}
+                  {{ form.first_name.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.last_name.id_for_label }}">Last name</label>
+                  {{ form.last_name }}
+                  {{ form.last_name.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.phone.id_for_label }}">Phone</label>
+                  {{ form.phone }}
+                  {{ form.phone.errors }}
+                </div>
+              </div>
+              <div class="col-12">
+                <p class="form-label-outside">Shipping address</p>
+              </div>
+              <div class="col-12">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.address_line1.id_for_label }}">Street address</label>
+                  {{ form.address_line1 }}
+                  {{ form.address_line1.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.address_line2.id_for_label }}">Apt / suite</label>
+                  {{ form.address_line2 }}
+                  {{ form.address_line2.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.address_city.id_for_label }}">City</label>
+                  {{ form.address_city }}
+                  {{ form.address_city.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.address_state.id_for_label }}">State</label>
+                  {{ form.address_state }}
+                  {{ form.address_state.errors }}
+                </div>
+              </div>
+              <div class="col-sm-6">
+                <div class="form-wrap">
+                  <label class="form-label-outside" for="{{ form.address_zip.id_for_label }}">ZIP</label>
+                  {{ form.address_zip }}
+                  {{ form.address_zip.errors }}
+                </div>
+              </div>
+              <div class="col-12">
+                <button class="button button-lg button-primary" type="submit">Save profile</button>
+              </div>
+            </div>
+          </form>
+{% endblock %}
+{% block extra_js %}
+<script src="{% static 'js/address-autocomplete.js' %}"></script>
+{% endblock %}