feat(chat): persistance bornee du brouillon custom chat par projet/layout (#182)

crates/domain/src/ports.rs

@@ -35,6 +35,7 @@ use crate::background_task::{
     BackgroundTask, BackgroundTaskKind, BackgroundTaskResult, BackgroundTaskWakePolicy,
 };
 use crate::chat_attachment::{ChatAttachment, ChatAttachmentId, ChatAttachmentSourceKind};
+use crate::chat_draft::{ChatDraft, ChatDraftKey};
 use crate::device::{AuthenticatedDevice, DeviceId, PairedDevice};
 use crate::events::DomainEvent;
 use crate::ids::{
@@ -1251,6 +1252,23 @@ pub trait ChatAttachmentStore: Send + Sync {
     ) -> Result<Vec<ChatAttachment>, ChatAttachmentStoreError>;
 }
 
+/// Persistence port for project-scoped custom chat drafts.
+#[async_trait]
+pub trait ChatDraftStore: Send + Sync {
+    /// Reads one draft. Missing entries return `Ok(None)`.
+    async fn read(
+        &self,
+        root: &ProjectPath,
+        key: ChatDraftKey,
+    ) -> Result<Option<ChatDraft>, StoreError>;
+
+    /// Saves or replaces one draft.
+    async fn save(&self, root: &ProjectPath, draft: ChatDraft) -> Result<(), StoreError>;
+
+    /// Clears one draft. Missing entries are a no-op.
+    async fn clear(&self, root: &ProjectPath, key: ChatDraftKey) -> Result<(), StoreError>;
+}
+
 /// Errors from the sprint store.
 #[derive(Debug, Clone, PartialEq, Eq, Error)]
 pub enum SprintStoreError {