migrate local.rs and memory.rs to use index

- Add Store::all_keys() method for iteration
- Convert store.nodes.get() → store.get_node()
- Convert store.nodes.contains_key() → store.contains_key()
- Convert store.nodes.values() iteration → all_keys + get_node

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/hippocampus/memory.rs

@@ -26,7 +26,7 @@ impl MemoryNode {
 
     /// Load from an already-open store.
     pub fn from_store(store: &Store, key: &str) -> Option<Self> {
-        let node = store.nodes.get(key)?;
+        let node = store.get_node(key).ok()??;
 
         // If set, tag links to nodes created after this timestamp as (new)
         let older_than: i64 = std::env::var("POC_MEMORIES_OLDER_THAN")
@@ -45,7 +45,9 @@ impl MemoryNode {
                 continue;
             };
 
-            let is_new = older_than > 0 && store.nodes.get(neighbor_key.as_str())
+            let is_new = older_than > 0 && store.get_node(neighbor_key)
+                .ok()
+                .flatten()
                 .map(|n| n.created_at > older_than)
                 .unwrap_or(false);
 
@@ -61,7 +63,7 @@ impl MemoryNode {
 
         Some(MemoryNode {
             key: key.to_string(),
-            content: node.content.clone(),
+            content: node.content,
             links,
             version: node.version,
             weight: node.weight,