Address PR review: rename to eda_visibility, merge migrations, API versioning

Changes based on jbtronics' review of PR #1241:

- Rename kicad_export -> eda_visibility (entities, forms, templates,
  translations, tests) with nullable bool for system default support
- Merge two database migrations into one (Version20260211000000)
- Rename createCachedJsonResponse -> createCacheableJsonResponse
- Change bool $apiV2 -> int $apiVersion with version validation
- EDA visibility field only shown for part parameters, not other entities
- PopulateKicadCommand: check alternative names of footprints/categories
- PopulateKicadCommand: support external JSON mapping file (--mapping-file)
- Ship default mappings JSON at contrib/kicad-populate/default_mappings.json
- Add system-wide defaultEdaVisibility setting in KiCadEDASettings
- Add KiCad HTTP Library v2 spec link in controller docs

templates/parts/edit/_specifications.html.twig

@@ -14,7 +14,7 @@
             <th>{% trans %}specifications.unit{% endtrans %}</th>
             <th>{% trans %}specifications.text{% endtrans %}</th>
             <th>{% trans %}specifications.group{% endtrans %}</th>
-            <th title="{% trans %}specifications.kicad_export.help{% endtrans %}"><i class="fas fa-bolt fa-fw"></i></th>
+            <th title="{% trans %}specifications.eda_visibility.help{% endtrans %}"><i class="fas fa-bolt fa-fw"></i></th>
             <th></th>
         </tr>
         </thead>

templates/parts/edit/edit_form_styles.html.twig

@@ -33,7 +33,7 @@
             {{ form_row(form.supplier_product_url,  {'attr': {'class': 'form-control-sm'}}) }}
             {{ form_widget(form.obsolete) }}
             {{ form_widget(form.pricesIncludesVAT) }}
-            {{ form_widget(form.kicad_export) }}
+            {{ form_widget(form.eda_visibility) }}
         </td>
         <td>
             <div {{ collection.controller(form.pricedetails, 'pricedetails.edit.delete.confirm') }}>
@@ -80,7 +80,9 @@
         <td {{ stimulus_controller('pages/latex_preview', {"unit": true}) }}>{{ form_widget(form.unit, {"attr": {"data-pages--parameters-autocomplete-target": "unit", "data-pages--latex-preview-target": "input"}}) }}{{ form_errors(form.unit) }}<span {{ stimulus_target('pages/latex_preview', 'preview') }}></span></td>
         <td>{{ form_widget(form.value_text) }}{{ form_errors(form.value_text) }}</td>
         <td>{{ form_widget(form.group) }}{{ form_errors(form.group) }}</td>
-        <td class="text-center">{{ form_widget(form.kicad_export) }}</td>
+        {% if form.eda_visibility is defined %}
+        <td class="text-center">{{ form_widget(form.eda_visibility) }}</td>
+        {% endif %}
         <td>
             <button type="button" class="btn btn-danger btn-sm order_btn_delete position-relative {% if form.parent.vars.allow_delete is defined and  not form.parent.vars.allow_delete %}disabled{% endif %}"
                     {{ collection.delete_btn() }} title="{% trans %}orderdetail.delete{% endtrans %}">