Phase 0 : entités, migrations, API Platform, PostGIS

- API Platform + Doctrine ORM + jsor/doctrine-postgis installés
- 6 entités Symfony (SargassumObservation, SargassumForecast,
  DataIngestionJob, CoastalPoint, ImpactScore, UserFeedback)
- Migration initiale manuelle avec CREATE EXTENSION postgis,
  toutes les tables, index GIST et BTREE
- doctrine.yaml configuré pour PostgreSQL 16 + types PostGIS
- Roadmap Phase 0 complète

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

backend/composer.json

@@ -7,15 +7,31 @@
         "php": ">=8.2",
         "ext-ctype": "*",
         "ext-iconv": "*",
+        "api-platform/doctrine-orm": "^4.3",
+        "api-platform/symfony": "^4.3",
+        "doctrine/doctrine-bundle": "^2.18",
+        "doctrine/doctrine-migrations-bundle": "^3.7",
+        "doctrine/orm": "^3.6",
+        "jsor/doctrine-postgis": "^2.4",
+        "nelmio/cors-bundle": "^2.6",
+        "phpdocumentor/reflection-docblock": "^6.0",
+        "phpstan/phpdoc-parser": "^2.3",
+        "symfony/asset": "7.4.*",
         "symfony/console": "7.4.*",
         "symfony/dotenv": "7.4.*",
+        "symfony/expression-language": "7.4.*",
         "symfony/flex": "^2",
         "symfony/framework-bundle": "7.4.*",
+        "symfony/property-access": "7.4.*",
+        "symfony/property-info": "7.4.*",
         "symfony/runtime": "7.4.*",
+        "symfony/security-bundle": "7.4.*",
+        "symfony/serializer": "7.4.*",
+        "symfony/twig-bundle": "7.4.*",
+        "symfony/uid": "7.4.*",
+        "symfony/validator": "7.4.*",
         "symfony/yaml": "7.4.*"
     },
-    "require-dev": {
-    },
     "config": {
         "allow-plugins": {
             "php-http/discovery": true,