rename agent: fix tool calls and target override

- Add memory_rename tool (in-place rename, preserves content and links)
- Update rename.agent prompt to use memory_rename() instead of text output
- Fix {{rename}} placeholder to respect --target keys when provided
- Add format_rename_targets() for targeted rename runs

src/agent/tools/memory.rs

@@ -35,6 +35,9 @@ pub fn definitions() -> Vec<ToolDef> {
         ToolDef::new("memory_weight_set",
             "Set a node's weight directly (0.01 to 1.0).",
             json!({"type":"object","properties":{"key":{"type":"string"},"weight":{"type":"number","description":"0.01 to 1.0"}},"required":["key","weight"]})),
+        ToolDef::new("memory_rename",
+            "Rename a node key in place. Same content, same links, new key.",
+            json!({"type":"object","properties":{"old_key":{"type":"string"},"new_key":{"type":"string"}},"required":["old_key","new_key"]})),
         ToolDef::new("memory_supersede",
             "Mark a node as superseded by another (sets weight to 0.01).",
             json!({"type":"object","properties":{"old_key":{"type":"string"},"new_key":{"type":"string"},"reason":{"type":"string"}},"required":["old_key","new_key"]})),
@@ -116,6 +119,15 @@ pub fn dispatch(name: &str, args: &serde_json::Value, provenance: Option<&str>)
         "memory_link_set" | "memory_link_add" | "memory_used" | "memory_weight_set" => {
             with_store(name, args, prov)
         }
+        "memory_rename" => {
+            let old_key = get_str(args, "old_key")?;
+            let new_key = get_str(args, "new_key")?;
+            let mut store = Store::load().map_err(|e| anyhow::anyhow!("{}", e))?;
+            let resolved = store.resolve_key(old_key).map_err(|e| anyhow::anyhow!("{}", e))?;
+            store.rename_node(&resolved, new_key).map_err(|e| anyhow::anyhow!("{}", e))?;
+            store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
+            Ok(format!("Renamed '{}' → '{}'", resolved, new_key))
+        }
         "memory_supersede" => {
             let old_key = get_str(args, "old_key")?;
             let new_key = get_str(args, "new_key")?;