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/system.menu.content.yml

@@ -0,0 +1,13 @@
+uuid: eb4f4d6b-825a-41f2-8510-942aa6b32677
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - navigation
+_core:
+  default_config_hash: nqVwm91Uyib_rvFaNPF1MdYqHlmZ38w5rsOVVy4uWDw
+id: content
+label: Content
+description: 'Content task links'
+locked: true