memory_links: return typed Vec<LinkInfo> with node weights

- hippocampus::memory_links now returns Vec<LinkInfo> with key,
  link_strength, and node_weight for each neighbor
- Unified memory_tool! macro: mut/ref as token, single main rule
- All tools use serde serialize/deserialize for RPC consistency
- jsonargs handlers now work in client mode (RPC to daemon)
- cli/graph.rs formats LinkInfo for display

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

src/hippocampus/mod.rs

@@ -84,15 +84,29 @@ pub fn memory_search(
         .collect::<Vec<_>>().join("\n"))
 }
 
-pub fn memory_links(store: &Store, _provenance: &str, key: &str) -> Result<String> {
+/// Info about a linked neighbor node.
+#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub struct LinkInfo {
+    pub key: String,
+    pub link_strength: f32,
+    pub node_weight: f32,
+}
+
+pub fn memory_links(store: &Store, _provenance: &str, key: &str) -> Result<Vec<LinkInfo>> {
     let node = MemoryNode::from_store(store, key)
         .ok_or_else(|| anyhow::anyhow!("node not found: {}", key))?;
-    let mut out = format!("Neighbors of '{}':\n", key);
-    for (target, strength, is_new) in &node.links {
-        let tag = if *is_new { " (new)" } else { "" };
-        out.push_str(&format!("  ({:.2}) {}{}\n", strength, target, tag));
+    let mut links = Vec::new();
+    for (target, strength, _is_new) in &node.links {
+        let node_weight = store.nodes.get(target.as_str())
+            .map(|n| n.weight)
+            .unwrap_or(0.5);
+        links.push(LinkInfo {
+            key: target.clone(),
+            link_strength: *strength,
+            node_weight,
+        });
     }
-    Ok(out)
+    Ok(links)
 }
 
 pub fn memory_link_set(store: &mut Store, _provenance: &str, source: &str, target: &str, strength: f32) -> Result<String> {