shouldSkipDuringSync was at 17.6% — only the no-sync-peer return ran.
Six tests for each exit path:

- no sync peer: syncCoordinator nil -> false
- not syncing: FSM RUNNING -> false
- announcement below sync peer height -> true
- announcement from non-sync peer -> true
- originator string fails to decode -> true (error short-circuit)
- happy path: syncing, height ok, sender == sync peer -> false

Lifts shouldSkipDuringSync 17.6% -> 100%. Package total 74.9% -> 75.1%.

Both functions were unexercised: handleBanEvent at 36.4% (only the
non-add early return ran via integration), disconnectBannedPeerByID
at 0%.

Six tests across the dispatch chain:

- handleBanEvent: non-add action, empty PeerID, invalid PeerID decode,
  valid PeerID dispatching to disconnectBannedPeerByID
- disconnectBannedPeerByID: peer found in connected list (registry
  removal), peer not in connected list (no mutation)

MockServerP2PClient.GetPeers gains an optional peers field for tests
that need to drive specific connected-peer lists. Existing callers
fall through to the previous empty-PeerInfo default.

Lifts handleBanEvent 36.4% -> 100%, disconnectBannedPeerByID 0% -> 100%.
Package total 75.1% -> 75.7%.

Apply gofmt to mock.go (struct field alignment) and reorder imports in
server_handler_test.go (alphabetical: go-bt before go-p2p-message-bus).
Adds the missing blank line before the merged-in cleanup tests block.

Sixteen Client.go methods sat at 0% coverage — none of the catchup
recording, reputation update, validity reporting, peer-info, or
byte-accounting wrappers had unit tests. The wrappers are uniform:
build proto, call gRPC, propagate gRPC errors, return service error
on Ok/Success false, otherwise return nil.

Tests cover the three exit paths per method using the existing
MockPeerServiceClient pattern:

- ok / grpc_error / not_ok for: RecordCatchupAttempt, RecordCatchupSuccess,
  RecordCatchupFailure, RecordCatchupMalicious, UpdateCatchupError,
  UpdateCatchupReputation, RecordBytesDownloaded
- ok_specific_peer / ok_all_peers / grpc_error / not_ok for ResetReputation
- ok / grpc_error / not_success for ReportValidSubtree, ReportValidBlock
- ok / grpc_error for GetPeersForCatchup, GetPeerRegistry, IsPeerMalicious,
  IsPeerUnhealthy
- found / not_found / grpc_error for GetPeer

MockPeerServiceClient gains a RecordBytesDownloadedFunc field — the
existing method always returned Ok=true, blocking error/!ok testing.
The fallback preserves the prior behaviour.

Coverage: each of the 16 wrappers 0% -> 100%, package total 75.7% -> 80.1%.
NewClient / NewClientWithAddress remain at 0% (real gRPC dial, out of
scope for unit tests).