feat(storage): add generic object storage adapter with CQRS traits, key validation, StorageConfig, and cargo-generate integration

crates/presentation/src/handlers/storage_example.rs

@@ -0,0 +1,27 @@
+// Example: stream a stored file as an HTTP response.
+// Remove this file or replace with your own handlers.
+//
+// To use, add to your router:
+//   .route("/files/*key", get(storage_example::get_file))
+//
+// use axum::{
+//     body::Body,
+//     extract::{Path, State},
+//     http::StatusCode,
+//     response::IntoResponse,
+// };
+// use futures::StreamExt;
+// use crate::state::AppState;
+//
+// pub async fn get_file(
+//     Path(key): Path<String>,
+//     State(state): State<AppState>,
+// ) -> Result<impl IntoResponse, StatusCode> {
+//     let stream = state
+//         .storage
+//         .get(&key)
+//         .await
+//         .map_err(|_| StatusCode::NOT_FOUND)?;
+//     let body = Body::from_stream(stream.map(|r| r.map_err(|e| e.to_string())));
+//     Ok(body)
+// }