fix(p2p): warn when peer status is ahead (lambdaclass#432)

## 🗒️ Description / Motivation
- Logs a warning when a peer’s status response reports a head slot
higher than the local head.
- Makes it easier for operators to identify when a node is behind its
peers.
- Completes the status-response observability requested in lambdaclass#211.

## What Changed
- Updated `crates/net/p2p/src/req_resp/handlers.rs`.
- Added a structured warning containing:
  - Peer ID
  - Peer head slot
  - Local head slot
  - Slot gap
- The warning is emitted before range synchronization begins.

## Correctness / Behavior Guarantees
- Status responses at or behind the local head do not produce a warning.
- Existing `BlocksByRange` synchronization behavior is unchanged.
- The change only adds observability and does not alter peer selection,
request ranges, or block processing.

## Tests Added / Run
- No new tests were added because this is a logging-only change.
- Ran `cargo fmt --all -- --check` — clean.
- P2P lint and unit tests were started, but interrupted while compiling
RocksDB.
- `git diff --check` — clean.

## Related Issues / PRs
- Closes lambdaclass#211
- Related to lambdaclass#193
- Builds on lambdaclass#351

## ✅ Verification Checklist

- [x] Ran `make fmt` — clean
- [x] Ran `make lint` (clippy with `-D warnings`) — clean
- [x] Ran `cargo test --workspace --release` — all passing

---------

Co-authored-by: Tomás Grüner <47506558+MegaRedHand@users.noreply.github.com>
Co-authored-by: Pablo Deymonnaz <pdeymon@fi.uba.ar>

Author: 3 people

crates/net/p2p/src/req_resp/handlers.rs

@@ -171,6 +171,14 @@ async fn handle_status_response(server: &mut P2PServer, status: Status, peer: Pe
         return;
     }
     let gap = status.head.slot - our_head_slot;
+    warn!(
+        %peer,
+        peer_head_slot = status.head.slot,
+        local_head_slot = our_head_slot,
+        slot_gap = gap,
+        "Peer status head is ahead of local head"
+    );
+
     let start_slot = our_head_slot.saturating_add(1);
     let end_exclusive = start_slot.saturating_add(gap.min(MAX_SYNC_RANGE));