perf(get): reuse reader paths and lock namespaces (#6015)

Co-authored-by: heihutu <heihutu@gmail.com>

crates/lock/src/namespace/mod.rs

@@ -180,6 +180,11 @@ impl NamespaceLock {
         Self::Local(LocalLock::new(namespace, manager))
     }
 
+    /// Create a local namespace lock that shares an existing namespace allocation.
+    pub fn with_local_manager_shared(namespace: Arc<str>, manager: Arc<crate::GlobalLockManager>) -> Self {
+        Self::Local(LocalLock::new_shared(namespace, manager))
+    }
+
     /// Create namespace lock with clients
     /// Uses DistributedLock with appropriate quorum
     pub fn with_clients(namespace: String, clients: Vec<Arc<dyn LockClient>>) -> Self {
@@ -195,6 +200,11 @@ impl NamespaceLock {
         Self::Distributed(DistributedLock::new(namespace, clients, quorum))
     }
 
+    /// Create a namespace lock that shares an existing namespace allocation.
+    pub fn with_clients_and_quorum_shared(namespace: Arc<str>, clients: Vec<Arc<dyn LockClient>>, quorum: usize) -> Self {
+        Self::Distributed(DistributedLock::new_shared(namespace, clients, quorum))
+    }
+
     /// Get namespace identifier
     pub fn namespace(&self) -> &str {
         match self {