feat(enhance): discard, tests against a mock ComfyUI, docs (#192)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/database/enhance_dao.rs

@@ -93,8 +93,11 @@ pub trait EnhanceJobDao: Sync + Send {
     fn insert(&mut self, job: &EnhanceJobRow) -> Result<(), DbError>;
     fn get(&mut self, id: &str) -> Result<Option<EnhanceJobRow>, DbError>;
     /// Newest first.
-    fn list_for_hash(&mut self, original_hash: &str, limit: i64)
-    -> Result<Vec<EnhanceJobRow>, DbError>;
+    fn list_for_hash(
+        &mut self,
+        original_hash: &str,
+        limit: i64,
+    ) -> Result<Vec<EnhanceJobRow>, DbError>;
     /// Jobs the poller still has to advance (`queued` / `running`).
     fn list_active(&mut self) -> Result<Vec<EnhanceJobRow>, DbError>;
     fn update(&mut self, id: &str, update: &JobUpdate) -> Result<(), DbError>;
@@ -325,7 +328,11 @@ mod tests {
         assert!(a.updated_at >= 100);
 
         d.discard("b").unwrap();
-        assert_eq!(d.list_for_hash("h1", 10).unwrap().len(), 1, "discarded hidden");
+        assert_eq!(
+            d.list_for_hash("h1", 10).unwrap().len(),
+            1,
+            "discarded hidden"
+        );
 
         // Prune drops only old, finished jobs (updated_at was just bumped
         // for `a`; `c` is active).