feat: allow --list to accept item IDs for filtering

- Local and client/server modes now support ID-based filtering
- keep -l 1 2 3 lists specific items by ID
- keep -l --ids-only 1 2 3 outputs just those IDs
- Server API adds optional 'ids' query parameter to GET /api/item/
- KeepClient.list_items gains ids parameter

src/client.rs

@@ -253,6 +253,7 @@ impl KeepClient {
 
     pub fn list_items(
         &self,
+        ids: &[i64],
         tags: &[String],
         order: &str,
         start: u64,
@@ -268,6 +269,15 @@ impl KeepClient {
         params.push(("order".to_string(), order.to_string()));
         params.push(("start".to_string(), start.to_string()));
         params.push(("count".to_string(), count.to_string()));
+        if !ids.is_empty() {
+            params.push((
+                "ids".to_string(),
+                ids.iter()
+                    .map(|i| i.to_string())
+                    .collect::<Vec<_>>()
+                    .join(","),
+            ));
+        }
         if !tags.is_empty() {
             params.push(("tags".to_string(), tags.join(",")));
         }