fix(914): thread-local ALL_OPS/VECTOR_CLOCK in cfg(test) so compaction tests don't race

Root cause was not the persist channel (the test-mode channel is unbounded
and its receiver is leaked, so sends never fail). It was that `ALL_OPS` and
`VECTOR_CLOCK` were process-wide `OnceLock` globals while `CRDT_STATE` was
already thread-local — so one test thread's `apply_compaction` would prune
another test thread's freshly-written ops out of the shared journal, and
the subsequent `all_ops_json()` read in `compaction_reduces_ops` would
return fewer than the 5 it had just written.

Mirror the pattern already used for `CRDT_STATE` and `SnapshotState`: in
`cfg(test)` use thread-local `OnceLock<Mutex<...>>`s for the op journal and
vector clock, accessed via new `all_ops_lock()` / `vector_clock_lock()`
helpers. Production code path is unchanged (still the global statics set
during `init()`).

Touches ops/read/snapshot call sites to go through the helpers. Note in
passing that this overlaps backlog story 518; that story is about the
production-side persist path, this is the cfg(test)-only journal-isolation
slice.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/src/crdt_state/state/mod.rs

@@ -35,8 +35,8 @@ pub(super) use indices::{
     rebuild_index, rebuild_merge_job_index, rebuild_node_index, rebuild_test_job_index,
     rebuild_token_index,
 };
-pub(crate) use statics::{ALL_OPS, VECTOR_CLOCK};
 pub(super) use statics::{SYNC_TX, track_op};
+pub(crate) use statics::{all_ops_lock, vector_clock_lock};
 
 // ── CrdtState struct ─────────────────────────────────────────────────
 
@@ -152,6 +152,13 @@ pub fn init_for_test() {
     });
     let _ = statics::CRDT_EVENT_TX.get_or_init(|| broadcast::channel::<CrdtEvent>(256).0);
     let _ = statics::SYNC_TX.get_or_init(|| broadcast::channel::<SignedOp>(1024).0);
-    let _ = statics::ALL_OPS.get_or_init(|| Mutex::new(Vec::new()));
-    let _ = statics::VECTOR_CLOCK.get_or_init(|| Mutex::new(VectorClock::new()));
+    // Per-thread op journal + vector clock — keeps parallel tests' writes
+    // from corrupting each other's view of ALL_OPS (notably, one thread's
+    // `apply_compaction` could otherwise prune another thread's ops).
+    statics::ALL_OPS_TL.with(|lock| {
+        let _ = lock.set(Mutex::new(Vec::new()));
+    });
+    statics::VECTOR_CLOCK_TL.with(|lock| {
+        let _ = lock.set(Mutex::new(VectorClock::new()));
+    });
 }