Add bounded commit-pinned Hugging Face source streaming

crates/remora-hf-source/src/error.rs

@@ -0,0 +1,25 @@
+use std::time::Duration;
+
+use thiserror::Error;
+
+#[derive(Clone, Debug, Eq, Error, PartialEq)]
+pub enum HfSourceError {
+    #[error("Hugging Face source request is invalid")]
+    InvalidRequest,
+    #[error("Hugging Face source authorization failed")]
+    Authorization,
+    #[error("Hugging Face source was not found")]
+    NotFound,
+    #[error("Hugging Face source changed")]
+    SourceChanged,
+    #[error("Hugging Face source returned an unsupported entry")]
+    UnsupportedEntry,
+    #[error("Hugging Face source response is invalid")]
+    InvalidResponse,
+    #[error("Hugging Face source inventory is invalid")]
+    InvalidInventory,
+    #[error("Hugging Face inventory capacity is exhausted")]
+    Capacity,
+    #[error("Hugging Face source failed transiently")]
+    Transient { retry_after: Option<Duration> },
+}