Add household support: multi-household isolation, each with own admin and users, 38 tests

templates/base.html

@@ -11,7 +11,8 @@
         <span class="brand">🍽 Meal Tracker</span>
         {% if session.user_id %}
         <div class="nav-right">
-            <span class="nav-user">{{ session.username }}</span>
+            <span class="nav-household">{{ session.household_name }}</span>
+            <span class="nav-user">{{ session.username }}{% if session.is_admin %} (admin){% endif %}</span>
             <a class="btn btn-sm" href="{{ url_for('auth.logout') }}">Logout</a>
         </div>
         {% endif %}

templates/register.html

@@ -1,7 +1,7 @@
 {% extends "base.html" %}
 {% block title %}Register — Meal Tracker{% endblock %}
 {% block content %}
-<div class="form-card">
+<div class="form-card register-card">
     <h2>Create Account</h2>
     <form method="POST">
         <label for="username">Username</label>
@@ -13,6 +13,42 @@
         <label for="confirm">Confirm Password</label>
         <input type="password" id="confirm" name="confirm" required>
 
+        <fieldset class="household-section">
+            <legend>Household</legend>
+
+            <label class="radio-label">
+                <input type="radio" name="household_action" value="join" checked
+                       onchange="document.getElementById('join-block').hidden=false;
+                                document.getElementById('create-block').hidden=true;">
+                Join an existing household
+            </label>
+            <div id="join-block" class="household-block">
+                <select name="household_id" class="select-input">
+                    <option value="">— Select —</option>
+                    {% for h in households %}
+                    <option value="{{ h.id }}">{{ h.name }}</option>
+                    {% endfor %}
+                </select>
+                {% if not households %}
+                <p class="hint">No households yet. Create one below!</p>
+                {% endif %}
+            </div>
+
+            <label class="radio-label">
+                <input type="radio" name="household_action" value="create"
+                       onchange="document.getElementById('join-block').hidden=true;
+                                document.getElementById('create-block').hidden=false;"
+                       {% if not households %}checked{% endif %}>
+                Create a new household
+            </label>
+            <div id="create-block" class="household-block" hidden>
+                <input type="text" name="new_household_name"
+                       placeholder="Household name (e.g. The Smiths)"
+                       class="text-input">
+                <p class="hint">You'll be the admin of this household.</p>
+            </div>
+        </fieldset>
+
         <button type="submit" class="btn btn-primary">Register</button>
     </form>
     <p class="form-footer">