feat: serve derivative files via GET /assets/{id}/derivatives/{profile}

- ReadDerivativeHandler queries DerivativeRepository + FileStoragePort
- Profile URL param: thumbnail, thumbnail_large, web_optimized, video_sd
- Immutable cache headers (derivatives don't change once generated)
- Wired into bootstrap catalog service builder

crates/presentation/src/handlers/assets.rs

@@ -10,8 +10,8 @@ use api_types::{
 };
 use application::{
     catalog::{
-        GetAssetQuery, GetTimelineQuery, ReadAssetFileQuery, RegisterAssetCommand,
-        UpdateMetadataCommand,
+        GetAssetQuery, GetTimelineQuery, ReadAssetFileQuery, ReadDerivativeQuery,
+        RegisterAssetCommand, UpdateMetadataCommand,
     },
     organization::TagAssetCommand,
     storage::IngestAssetCommand,
@@ -152,6 +152,40 @@ pub async fn tag_asset(
     Ok((StatusCode::CREATED, Json(TagResponse::from_domain(&tag))))
 }
 
+pub async fn serve_derivative(
+    State(state): State<AppState>,
+    _claims: JwtClaims,
+    Path((asset_id, profile)): Path<(uuid::Uuid, String)>,
+) -> Result<Response, AppError> {
+    let profile = parse_derivative_profile(&profile)?;
+    let query = ReadDerivativeQuery {
+        asset_id: SystemId::from_uuid(asset_id),
+        profile,
+    };
+    let result = state.catalog.read_derivative.execute(query).await?;
+
+    Response::builder()
+        .status(StatusCode::OK)
+        .header(header::CONTENT_TYPE, &result.mime_type)
+        .header(header::CONTENT_LENGTH, result.data.len())
+        .header(header::CACHE_CONTROL, "public, max-age=31536000, immutable")
+        .body(Body::from(result.data))
+        .map_err(|e| AppError::from(DomainError::Internal(e.to_string())))
+}
+
+fn parse_derivative_profile(s: &str) -> Result<domain::entities::DerivativeProfile, AppError> {
+    use domain::entities::DerivativeProfile;
+    match s {
+        "thumbnail" | "thumbnail_square" => Ok(DerivativeProfile::ThumbnailSquare),
+        "thumbnail_large" => Ok(DerivativeProfile::ThumbnailLarge),
+        "web" | "web_optimized" => Ok(DerivativeProfile::WebOptimized),
+        "video_sd" => Ok(DerivativeProfile::VideoSd),
+        _ => Err(AppError::from(DomainError::Validation(format!(
+            "Unknown derivative profile: {s}"
+        )))),
+    }
+}
+
 fn parse_asset_type(s: &str) -> Result<AssetType, AppError> {
     match s {
         "image" => Ok(AssetType::Image),

crates/presentation/src/routes.rs

@@ -29,6 +29,10 @@ pub fn api_v1_router() -> Router<AppState> {
         .route("/assets/{id}", get(assets::get_asset))
         .route("/assets/{id}/metadata", put(assets::update_metadata))
         .route("/assets/{id}/file", get(assets::serve_file))
+        .route(
+            "/assets/{id}/derivatives/{profile}",
+            get(assets::serve_derivative),
+        )
         .route("/assets/{id}/tags", post(assets::tag_asset))
         // sharing
         .route("/sharing", post(sharing::share_resource))

crates/presentation/src/state.rs

@@ -2,8 +2,8 @@ use std::sync::Arc;
 
 use application::{
     catalog::{
-        GetAssetHandler, GetTimelineHandler, ReadAssetFileHandler, RegisterAssetHandler,
-        UpdateMetadataHandler,
+        GetAssetHandler, GetTimelineHandler, ReadAssetFileHandler, ReadDerivativeHandler,
+        RegisterAssetHandler, UpdateMetadataHandler,
     },
     identity::{GetProfileHandler, LoginUserHandler, RegisterUserHandler},
     organization::{
@@ -41,6 +41,7 @@ pub struct CatalogHandlers {
     pub get_timeline: Arc<GetTimelineHandler>,
     pub update_metadata: Arc<UpdateMetadataHandler>,
     pub read_asset_file: Arc<ReadAssetFileHandler>,
+    pub read_derivative: Arc<ReadDerivativeHandler>,
     pub register_asset: Arc<RegisterAssetHandler>,
 }