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>

web/profiles/README.txt

@@ -0,0 +1,28 @@
+Installation profiles define additional steps that run after the base
+installation of Drupal is completed. They may also offer additional
+functionality and change the behavior of the site.
+
+WHAT TO PLACE IN THIS DIRECTORY?
+--------------------------------
+
+Place downloaded and custom installation profiles in this directory.
+Note that installation profiles are generally provided as part of a Drupal
+distribution.
+
+DOWNLOAD ADDITIONAL DISTRIBUTIONS
+---------------------------------
+
+Contributed distributions from the Drupal community may be downloaded at
+https://www.drupal.org/project/project_distribution.
+
+MULTISITE CONFIGURATION
+-----------------------
+
+In multisite configurations, installation profiles found in this directory are
+available to all sites during their initial site installation.
+
+MORE INFORMATION
+----------------
+
+Refer to the "Installation profiles" section of the README.md in the Drupal
+root directory for further information on extending Drupal with custom profiles.