feat: password change + split account/household settings UI

- New /change-password route: validates current password,
  enforces min 4 chars, requires confirmation match
- update_password() helper in models.py
- Dashboard UI split into two collapsible sections:
  👤 Account Settings (password, ntfy, delete account)
  🏠 Household Settings (admin only: public link, timezone,
     delete household)
- 14 new i18n keys with fr/de translations
- Restored accidentally dropped 'Delete My Account' key

templates/dashboard.html

@@ -85,15 +85,14 @@
 
 <div class="manage-section">
     <details class="manage-details">
-        <summary>{{ t('⚙ Account Settings') }}</summary>
+        <summary>{{ t('👤 Account Settings') }}</summary>
         <div class="manage-forms">
-            <form method="POST" action="{{ url_for('meals.delete_account') }}"
-                  onsubmit="return confirm(this.dataset.confirmMsg);"
-                  data-confirm-msg="{{ t('Delete YOUR account? This cannot be undone.') }}"
-                  class="manage-form">
-                <h4>{{ t('Delete My Account') }}</h4>
-                <input type="password" name="password" placeholder="{{ t('Enter your password to confirm') }}" required>
-                <button class="btn btn-danger">{{ t('Delete My Account') }}</button>
+            <form method="POST" action="{{ url_for('meals.change_password') }}" class="manage-form">
+                <h4>🔑 {{ t('Change Password') }}</h4>
+                <input type="password" name="current_password" placeholder="{{ t('Current password') }}" required>
+                <input type="password" name="new_password" placeholder="{{ t('New password') }}" required style="margin-top: 8px;">
+                <input type="password" name="confirm_password" placeholder="{{ t('Confirm new password') }}" required style="margin-top: 8px;">
+                <button type="submit" class="btn btn-primary btn-sm" style="margin-top: 8px;">{{ t('Change Password') }}</button>
             </form>
 
             <form method="POST" action="{{ url_for('meals.ntfy_settings') }}" class="manage-form">
@@ -113,7 +112,22 @@
                 </div>
             </form>
 
-            {% if is_admin %}
+            <form method="POST" action="{{ url_for('meals.delete_account') }}"
+                  onsubmit="return confirm(this.dataset.confirmMsg);"
+                  data-confirm-msg="{{ t('Delete YOUR account? This cannot be undone.') }}"
+                  class="manage-form">
+                <h4>{{ t('Delete My Account') }}</h4>
+                <p class="hint">{{ t('This will permanently delete your account and all your responses.') }}</p>
+                <input type="password" name="password" placeholder="{{ t('Enter your password to confirm') }}" required>
+                <button class="btn btn-danger">{{ t('Delete My Account') }}</button>
+            </form>
+        </div>
+    </details>
+
+    {% if is_admin %}
+    <details class="manage-details" style="margin-top: 8px;">
+        <summary>{{ t('🏠 Household Settings') }}</summary>
+        <div class="manage-forms">
             <form method="POST" action="{{ url_for('meals.admin_public_link') }}" class="manage-form">
                 <h4>🔗 {{ t('Public Sharing Link') }}</h4>
                 <p class="hint">{{ t('Share a read-only view of your household\'s meal status. The link is hard to guess — only people with it can see the data.') }}</p>
@@ -150,9 +164,7 @@
                 </select>
                 <button type="submit" class="btn btn-primary btn-sm" style="margin-top: 8px;">{{ t('Save') }}</button>
             </form>
-            {% endif %}
 
-            {% if is_admin %}
             <form method="POST" action="{{ url_for('meals.admin_delete_household') }}"
                   onsubmit="return confirm(this.dataset.confirmMsg);"
                   data-confirm-msg="{{ t('Delete the ENTIRE household and ALL members? This cannot be undone.') }}"
@@ -162,9 +174,9 @@
                 <input type="password" name="password" placeholder="{{ t('Enter your password to confirm') }}" required>
                 <button class="btn btn-danger">{{ t('Delete Household') }}</button>
             </form>
-            {% endif %}
         </div>
     </details>
+    {% endif %}
 </div>
 
 <script>