refactor : migrate VERSION file to config/version.yaml

Same versioning system as SIRH/Lesstime. Updates nuxt.config.ts,
Dockerfile, deploy.sh, auto-tag CI, and release script.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config/packages/api_platform.yaml

@@ -1,7 +1,7 @@
 api_platform:
     title: Inventory API
     description: API de gestion d'inventaire industriel — machines, pièces, composants, produits.
-    version: 1.9.1
+    version: 1.9.6
     defaults:
         stateless: false
         cache_headers: