add privacy page as standalone SPA view outside slide navigation

- New Kirby template/blueprint/JSON for privacy page (confidentialite slug)
- Standalone page state in slides store + router handling for non-nav pages
- Privacy.svelte view with background image, text blocks, footer
- Centralize vertical lines in App.svelte as fixed elements with per-slide visibility
- Footer privacy link language-aware (FR/EN)
- Portfolio mockup fix: read from default language for consistent EN display
- menu.php: add privacy page to Kirby panel navigation

refs #44

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

site/templates/portfolio.json.php

@@ -1,8 +1,11 @@
 <?php
 
+$defaultLang = kirby()->defaultLanguage()->code();
+
 $specificData = [
   'backgroundImage' => $page->backgroundImage()->toFile()?->url(),
-  'projects' => $page->children()->listed()->map(function($project) {
+  'projects' => $page->children()->listed()->map(function($project) use ($defaultLang) {
+    $mockupFile = $project->content($defaultLang)->mockup()->toFile();
     return [
       'title'          => $project->title()->value(),
       'slug'           => $project->slug(),
@@ -14,9 +17,9 @@ $specificData = [
                             'srcset'  => $f->srcset('gallery'),
                             'webp'    => $f->srcset('gallery-webp'),
                           ])->values(),
-      'mockup'                => $project->content(kirby()->defaultLanguage()->code())->mockup()->toFile()?->url(),
-      'mockupSrcset'          => $project->content(kirby()->defaultLanguage()->code())->mockup()->toFile()?->srcset('mockup'),
-      'mockupWebp'            => $project->content(kirby()->defaultLanguage()->code())->mockup()->toFile()?->srcset('mockup-webp'),
+      'mockup'                => $mockupFile?->url(),
+      'mockupSrcset'          => $mockupFile?->srcset('mockup'),
+      'mockupWebp'            => $mockupFile?->srcset('mockup-webp'),
       'galleryAnimationMode'   => $project->galleryAnimationMode()->value() ?: 'vertical',
       'secondsPerImage'        => $project->secondsPerImage()->isNotEmpty() ? (int) $project->secondsPerImage()->value() : 8,
       'galleryBackgroundColor' => $project->galleryBackgroundColor()->value(),

site/templates/privacy.json.php

@@ -0,0 +1,21 @@
+<?php
+
+$bodyBlocks = [];
+foreach ($page->body()->toBlocks() as $block) {
+  if ($block->type() === 'text') {
+    $bodyBlocks[] = [
+      'type' => 'text',
+      'html' => $block->content()->text()->value(),
+    ];
+  }
+}
+
+$specificData = [
+  'backgroundImage' => $page->backgroundImage()->toFile()?->url(),
+  'body'            => $bodyBlocks,
+];
+
+$pageData = array_merge($genericData, $specificData);
+
+header('Content-Type: application/json');
+echo json_encode($pageData);

site/templates/privacy.php

@@ -0,0 +1,2 @@
+<?php snippet('header') ?>
+<?php snippet('footer') ?>