feat: use postcard for redis serde (#6956)

* redo error handling in xredis

* give proper types to metadata fields

* add round-trip tests

* inline loader enum metadata fields

* postcard roundtrips

* prepare

* bump redis key version

* serde-binhum

* clippy

* fix

* fix frontend checking existence of component fields rather than non-null-ness

* prepare

packages/xredis/src/cache/locking/local.rs

@@ -3,11 +3,10 @@ use std::sync::atomic::{AtomicBool, Ordering};
 
 use dashmap::DashMap;
 use dashmap::mapref::entry::Entry;
+use eyre::{Result, WrapErr};
 use tokio::sync::Notify;
 use tokio::time::{Instant, timeout_at};
 
-use crate::Error;
-
 #[derive(Clone)]
 pub(in crate::cache) struct LockCoordinator {
     locks: Arc<DashMap<String, Arc<LockState>>>,
@@ -76,10 +75,7 @@ pub(in crate::cache) struct LockWaiter {
 }
 
 impl LockWaiter {
-    pub(in crate::cache) async fn wait(
-        self,
-        deadline: Instant,
-    ) -> Result<(), Error> {
+    pub(in crate::cache) async fn wait(self, deadline: Instant) -> Result<()> {
         loop {
             if self.state.released.load(Ordering::Acquire) {
                 return Ok(());
@@ -94,7 +90,7 @@ impl LockWaiter {
 
             timeout_at(deadline, notified)
                 .await
-                .map_err(|_| lock_timeout())?;
+                .wrap_err("waiting for local Redis cache lock")?;
         }
     }
 }
@@ -112,10 +108,3 @@ impl LockState {
         }
     }
 }
-
-fn lock_timeout() -> Error {
-    Error::LocalCacheTimeout {
-        released: 0,
-        total: 1,
-    }
-}