Provider: Initialization

Is your feature request related to a problem?

Provider names are currently stored as plain strings in the database. This means there's no single source of truth for valid
providers, leading to potential inconsistencies and making it harder to manage providers across organizations.

Describe the solution you'd like

Add a provider table to the global schema (similar to the recently added languages table). This would:

• Define all supported providers in one place
• Allow organizations to add credentials to their project referencing this table via foreign key
• Replace free-text provider strings with proper references, ensuring data consistency
• Make it easy to onboard new providers once and have them available across all orgs

L’issue ne nomme aucun fichier ni test. Commencez par localiser la languages table récemment ajoutée ainsi que le schéma ou les modèles où sont stockés les credentials du projet et les chaînes de provider. C’est terminé lorsque les providers pris en charge disposent d’une source globale, que les credentials y font référence et que les valeurs de provider existantes sont traitées de manière cohérente.