chore : rename Coltura to Starseed

- Rename project name across code, configs, docs, dev/prod infra
- Dev: DOCKER_APP_NAME + POSTGRES_DB switched to starseed, containers become php-starseed-fpm / nginx-starseed / starseed-db-1
- Dev: mount nginx.conf on default.conf instead of starseed.conf to avoid alphabetical-order clash with image's default site
- Makefile: export CURRENT_UID/CURRENT_GID at top level so docker compose builds (db-reset etc.) get them
- Prod: image registry path, container_name, volumes, vhost server_name + paths, DATABASE_URL, CORS, CI workflow
- Add doc/prompt-rename-prod.md with the migration runbook for the prod server (DB rename, FS move, vhost, Let's Encrypt)

migrations/Version20260417120000.php

@@ -11,7 +11,7 @@ use Doctrine\Migrations\AbstractMigration;
  * Module Sites - Ticket 1/4 : brique fondatrice de donnees.
  *
  * Cree la table `site` qui porte les etablissements physiques de l'instance
- * Coltura. La table est creee inconditionnellement : meme si SitesModule est
+ * Starseed. La table est creee inconditionnellement : meme si SitesModule est
  * desactive dans `config/modules.php`, la structure DB existe (pas de
  * dependance dure depuis Core, mais pas de coin d'ombre schema non plus).
  *