Initial Drupal site: content model + validation + Vue dashboard

- Content type "Ligne comptable" with Paragraphs "Répartition" (Compte + Montant)
- Taxonomies: Compte (9 comptes) and Client (unified client list)
- hook_node_presave + form validate: sum(répartition) must equal montant HT
- /dashboard route (progressive decoupling): Vue 3 app fetching JSON:API,
  computing solde par compte / par client client-side
- "Ajouter une ligne" opens the real Drupal node form in an AJAX modal
- Gin as default + admin theme
- 9 opening-balance lines seeded from suivi_compta_SASFigli2026_v2.ods

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

config/sync/image.style.thumbnail.yml

@@ -0,0 +1,23 @@
+uuid: a2daed2c-aa52-4587-ba09-a4234329c115
+langcode: en
+status: true
+dependencies: {  }
+_core:
+  default_config_hash: JXYDC3SLZUXSwnTjR9rBo6uZF3vDSZd8S7EA5ZOH7kM
+name: thumbnail
+label: 'Thumbnail (100×100)'
+effects:
+  1cfec298-8620-4749-b100-ccb6c4500779:
+    uuid: 1cfec298-8620-4749-b100-ccb6c4500779
+    id: image_scale
+    weight: 0
+    data:
+      width: 100
+      height: 100
+      upscale: false
+  c4eb9942-2c9e-4a81-949f-6161a44b6559:
+    uuid: c4eb9942-2c9e-4a81-949f-6161a44b6559
+    id: image_convert_avif
+    weight: 2
+    data:
+      extension: webp