Re-vendor the shared files from sneak/prompts at 0653579 (closes #52)

Takes .golangci.yml, .dockerignore, .gitignore, .editorconfig, the
workflow and REPO_POLICIES.md from sneak/prompts 0653579, with this
repository's own entries after the shared content. Lint (golangci-lint
v2.14.0) and test are Dockerfile phases that script/lint and script/test
build alone with a new CACHEBUST value, keeping Go's and golangci-lint's
caches; the image build depends on both. make fmt and make fmt-check also
format the markdown with prettier, pinned in yarn.lock. The agent
guidance moves to AGENTS.md. The Go code is fixed for what the new
configuration finds, and the AS and prefix detail reads now return the
rows' error after their loops.

Model: opus-5-5

internal/routewatch/peerhandler.go

@@ -1,7 +1,8 @@
 package routewatch
 
-// peerhandler.go provides batched peer tracking functionality for BGP route monitoring.
-// It tracks BGP peers from incoming UPDATE messages and maintains peer state in the database.
+// peerhandler.go provides batched peer tracking functionality for BGP route
+// monitoring. It tracks BGP peers from incoming UPDATE messages and maintains
+// peer state in the database.
 
 import (
 	"strconv"
@@ -44,9 +45,11 @@ type PeerHandler struct {
 	// Batching. mu guards peerBatch only: the flush goroutine takes the batch
 	// under mu and writes it after releasing mu, so HandleMessage waits for
 	// a database write only while peerBatch is at peerBatchMaxSize.
-	mu          sync.Mutex
-	peerBatch   []peerUpdate
-	batchTaken  sync.Cond     // signalled when the flush goroutine takes peerBatch; its L is &mu
+	mu        sync.Mutex
+	peerBatch []peerUpdate
+	// batchTaken is signalled when the flush goroutine takes peerBatch; its L
+	// is &mu.
+	batchTaken  sync.Cond
 	batchFullCh chan struct{} // wakes the flush goroutine when peerBatch is full
 	lastFlush   time.Time     // used only by the flush goroutine
 	stopCh      chan struct{}
@@ -104,8 +107,10 @@ func (h *PeerHandler) QueueCapacity() int {
 func (h *PeerHandler) HandleMessage(msg *ristypes.RISMessage) {
 	// Parse peer ASN from string
 	peerASN := 0
+
 	if msg.PeerASN != "" {
-		if asn, err := strconv.Atoi(msg.PeerASN); err == nil {
+		asn, err := strconv.Atoi(msg.PeerASN)
+		if err == nil {
 			peerASN = asn
 		}
 	}
@@ -139,10 +144,17 @@ func (h *PeerHandler) HandleMessage(msg *ristypes.RISMessage) {
 	}
 }
 
+// Stop gracefully stops the handler and flushes remaining batches
+func (h *PeerHandler) Stop() {
+	close(h.stopCh)
+	h.wg.Wait()
+}
+
 // flushLoop runs in a goroutine, the only one that writes the batch: it
 // flushes when the batch is full, periodically, and once more on Stop.
 func (h *PeerHandler) flushLoop() {
 	defer h.wg.Done()
+
 	ticker := time.NewTicker(peerBatchTimeout)
 	defer ticker.Stop()
 
@@ -172,6 +184,7 @@ func (h *PeerHandler) takeBatch() []peerUpdate {
 	if len(h.peerBatch) == 0 {
 		return nil
 	}
+
 	batch := h.peerBatch
 	h.peerBatch = make([]peerUpdate, 0, peerBatchSize)
 	h.batchTaken.Broadcast()
@@ -190,7 +203,8 @@ func (h *PeerHandler) flushBatch() {
 	// Deduplicate by peer IP, keeping the latest update for each peer
 	peerMap := make(map[string]peerUpdate)
 	for _, update := range batch {
-		if existing, ok := peerMap[update.peerIP]; !ok || update.timestamp.After(existing.timestamp) {
+		existing, ok := peerMap[update.peerIP]
+		if !ok || update.timestamp.After(existing.timestamp) {
 			peerMap[update.peerIP] = update
 		}
 	}
@@ -207,15 +221,11 @@ func (h *PeerHandler) flushBatch() {
 	}
 
 	// Process all peers in a single batch transaction
-	if err := h.db.UpdatePeerBatch(dbPeerMap); err != nil {
-		h.logger.Error("Failed to process peer batch", "error", err, "count", len(dbPeerMap))
+	err := h.db.UpdatePeerBatch(dbPeerMap)
+	if err != nil {
+		h.logger.Error("Failed to process peer batch",
+			"error", err, "count", len(dbPeerMap))
 	}
 
 	h.lastFlush = time.Now()
 }
-
-// Stop gracefully stops the handler and flushes remaining batches
-func (h *PeerHandler) Stop() {
-	close(h.stopCh)
-	h.wg.Wait()
-}