feat(sync): short-hex Debug for peer from (#98)

## Description

Remote peer identity in `Debug` for `InsertOrigin::Sync` and
`Event::RemoteInsert` was printed as a `[u8; 32]` integer list, unlike
other logs that use compact hex. This switches those fields to
`derive_more::Debug` with `hex::encode` of the **first 5 bytes**,
matching `iroh_base::PublicKey::fmt_short()` / `EndpointId` logging
style.

Also updates the `PeerIdBytes` doc line to refer to **`EndpointId`**,
and refreshes the TODO to suggest `iroh::EndpointId` (re-exported from
`iroh-base`) instead of outdated `PeerId` / `iroh-net` wording.

## Breaking Changes

None.

## Notes & open questions

Using `iroh::EndpointId` instead of `PeerIdBytes` (`[u8; 32]`) would be
a breaking public API change but give us stronger typing, validation and
built-in helpers (`fmt_short`, etc.). Happy to open a follow-up PR with
that.

## Change checklist

- [x] Self-review.
- [x] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [ ] Tests if relevant.
- [x] All breaking changes documented.

Author: cbenhagen

src/sync.rs

@@ -34,8 +34,8 @@ use crate::{
 /// Can be serialized to bytes with [serde] to transfer between peers.
 pub type ProtocolMessage = crate::ranger::Message<SignedEntry>;
 
-/// Byte representation of a `PeerId` from `iroh-net`.
-// TODO: PeerId is in iroh-net which iroh-docs doesn't depend on. Add iroh-base crate with `PeerId`.
+/// Byte representation of an iroh `EndpointId`.
+// TODO: Consider `iroh::EndpointId` instead of raw bytes (`iroh` re-exports it from `iroh-base`).
 pub type PeerIdBytes = [u8; 32];
 
 /// Max time in the future from our wall clock time that we accept entries for.
@@ -47,7 +47,7 @@ pub type ContentStatusCallback =
     Arc<dyn Fn(Hash) -> n0_future::boxed::BoxFuture<ContentStatus> + Send + Sync + 'static>;
 
 /// Event emitted by sync when entries are added.
-#[derive(Debug, Clone)]
+#[derive(derive_more::Debug, Clone)]
 pub enum Event {
     /// A local entry has been added.
     LocalInsert {
@@ -63,6 +63,8 @@ pub enum Event {
         /// Inserted entry.
         entry: SignedEntry,
         /// Peer that provided the inserted entry.
+        /// Debug matches [`iroh::PublicKey::fmt_short`] (first 5 bytes, lower hex).
+        #[debug("{}", hex::encode(&from[..5]))]
         from: PeerIdBytes,
         /// Whether download policies require the content to be downloaded.
         should_download: bool,
@@ -72,13 +74,15 @@ pub enum Event {
 }
 
 /// Whether an entry was inserted locally or by a remote peer.
-#[derive(Debug, Clone)]
+#[derive(derive_more::Debug, Clone)]
 pub enum InsertOrigin {
     /// The entry was inserted locally.
     Local,
     /// The entry was received from the remote node identified by [`PeerIdBytes`].
     Sync {
         /// The peer from which we received this entry.
+        /// Debug matches [`iroh::PublicKey::fmt_short`] (first 5 bytes, lower hex).
+        #[debug("{}", hex::encode(&from[..5]))]
         from: PeerIdBytes,
         /// Whether the peer claims to have the content blob for this entry.
         remote_content_status: ContentStatus,