feat: add initial

Signed-off-by: kjuulh <contact@kjuulh.io>

todos/SQ-023-node-recovery.md

@@ -0,0 +1,31 @@
+# SQ-023: Node Recovery / Catch-Up
+
+**Status:** `[ ] TODO`
+**Blocked by:** SQ-021, SQ-018
+**Priority:** Medium
+
+## Description
+
+A node that was offline catches up from peers or S3 when it rejoins.
+
+## Files to Create/Modify
+
+- `crates/sq-cluster/src/recovery.rs` - on-join catch-up logic
+- `crates/sq-server/src/grpc/cluster.rs` - FetchSegment RPC impl
+- `crates/sq-cluster/src/replication.rs` - integrate recovery into join flow
+
+## Recovery Flow
+
+1. Rejoining node contacts peers via seed list
+2. For each topic-partition, compare local latest offset with peers
+3. If peer has newer data: fetch missing segments via FetchSegment RPC
+4. If peer has also trimmed: fetch from S3
+5. Replay fetched segments into local WAL
+6. Mark node as "caught up" and start accepting writes
+
+## Acceptance Criteria
+
+- [ ] Node joins late: fetches missing data from peer, all messages readable
+- [ ] Node catches up from S3 when peer has trimmed that segment
+- [ ] Recovery doesn't block existing cluster operations
+- [ ] Recovery progress is logged