cli: convert simple commands to use memory_rpc

Commands now forward to daemon (or fallback to local store):
- query → memory_query
- journal tail → journal_tail
- graph link-set → memory_link_set
- graph link-add → memory_link_add
- weight-set → memory_weight_set
- node rename → memory_rename

Removes ~50 lines of duplicated store access code.

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

src/cli/node.rs

@@ -85,11 +85,11 @@ pub fn cmd_not_useful(key: &str) -> Result<(), String> {
 
 pub fn cmd_weight_set(key: &str, weight: f32) -> Result<(), String> {
     super::check_dry_run();
-    let mut store = store::Store::load()?;
-    let resolved = store.resolve_key(key)?;
-    let (old, new) = store.set_weight(&resolved, weight)?;
-    println!("Weight: {} {:.2} → {:.2}", resolved, old, new);
-    store.save()?;
+    let result = crate::mcp_server::memory_rpc(
+        "memory_weight_set",
+        serde_json::json!({"key": key, "weight": weight}),
+    ).map_err(|e| e.to_string())?;
+    println!("{}", result);
     Ok(())
 }
 
@@ -171,13 +171,12 @@ pub fn cmd_node_delete(key: &[String]) -> Result<(), String> {
 }
 
 pub fn cmd_node_rename(old_key: &str, new_key: &str) -> Result<(), String> {
-    // args are positional, always valid if present
     super::check_dry_run();
-    let mut store = store::Store::load()?;
-    let old_resolved = store.resolve_key(old_key)?;
-    store.rename_node(&old_resolved, new_key)?;
-    store.save()?;
-    println!("Renamed '{}' → '{}'", old_resolved, new_key);
+    let result = crate::mcp_server::memory_rpc(
+        "memory_rename",
+        serde_json::json!({"old_key": old_key, "new_key": new_key}),
+    ).map_err(|e| e.to_string())?;
+    println!("{}", result);
     Ok(())
 }