fix: livrable tickets #70 #100 #102 — UX surface scoping

- #70: implémentation suppression modèles locaux téléchargés
- #100: correction scroll OpenCode
- #102: correction fit TUI après switch/layout
- memory note scoping UX

crates/backend/src/dto.rs

@@ -1343,7 +1343,10 @@ impl From<FirstRunStateOutput> for FirstRunStateDto {
 // Local model servers (B35)
 // ---------------------------------------------------------------------------
 
-use application::{ListModelServersOutput, SaveModelServerInput, SaveModelServerOutput};
+use application::{
+    ListModelServersOutput, ModelArtifactView, ModelServerListItem, SaveModelServerInput,
+    SaveModelServerOutput,
+};
 use domain::model_server::{
     ExecutablePath, HfModelRef, LlamaCppOptions, LocalModelRef, LocalModelServerConfig,
     LocalModelServerKind, ModelPath, ModelServerEndpoint, ModelSource,
@@ -1492,6 +1495,9 @@ pub struct ModelServerConfigDto {
     /// Optional readiness warmup deadline override in seconds.
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub warmup_deadline_secs: Option<u64>,
+    /// Derived local artifact cache state.
+    #[serde(default)]
+    pub artifact: ModelArtifactDto,
 }
 
 impl ModelServerConfigDto {
@@ -1516,6 +1522,7 @@ impl ModelServerConfigDto {
             auto_start: config.auto_start,
             stop_policy: config.stop_policy.into(),
             warmup_deadline_secs: config.warmup_deadline_secs,
+            artifact: ModelArtifactDto::NotManaged,
         }
     }
 
@@ -1563,6 +1570,53 @@ impl ModelServerConfigDto {
     }
 }
 
+/// Local model artifact cache state on the IPC wire.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase", tag = "state")]
+pub enum ModelArtifactDto {
+    /// The configured source is not managed by IdeA's downloader.
+    NotManaged,
+    /// The configured source is managed but not present in cache.
+    Missing,
+    /// A download/prepare operation is currently running for this server.
+    Downloading,
+    /// The configured source is present in cache.
+    Downloaded {
+        /// Local artifact path.
+        path: String,
+        /// Total on-disk size when known.
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        size_bytes: Option<u64>,
+    },
+}
+
+impl Default for ModelArtifactDto {
+    fn default() -> Self {
+        Self::NotManaged
+    }
+}
+
+impl From<ModelArtifactView> for ModelArtifactDto {
+    fn from(view: ModelArtifactView) -> Self {
+        match view {
+            ModelArtifactView::NotManaged => Self::NotManaged,
+            ModelArtifactView::Missing => Self::Missing,
+            ModelArtifactView::Downloading => Self::Downloading,
+            ModelArtifactView::Downloaded { path, size_bytes } => {
+                Self::Downloaded { path, size_bytes }
+            }
+        }
+    }
+}
+
+impl From<ModelServerListItem> for ModelServerConfigDto {
+    fn from(item: ModelServerListItem) -> Self {
+        let mut dto = Self::from_domain(item.config);
+        dto.artifact = item.artifact.into();
+        dto
+    }
+}
+
 /// Response DTO for `preview_model_server_command`.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize)]
 #[serde(rename_all = "camelCase")]
@@ -1585,7 +1639,7 @@ impl From<ListModelServersOutput> for ModelServerConfigListDto {
         Self(
             out.servers
                 .into_iter()
-                .map(ModelServerConfigDto::from_domain)
+                .map(ModelServerConfigDto::from)
                 .collect(),
         )
     }