Re-vendor the shared files from sneak/prompts at dd4027b (closes #52)

Takes .golangci.yml, .dockerignore, .gitignore, .editorconfig, the
workflow and REPO_POLICIES.md from sneak/prompts dd4027b, keeping this
repository's own entries after the shared content. Lint (golangci-lint
v2.14.0) and test become Dockerfile phases that script/lint and
script/test build alone and uncached; the image build depends on both,
and script/cibuild bootstraps, runs script/check, then builds the image.
The agent guidance file moves to AGENTS.md. The Go code is fixed for
what the new configuration finds; reads that iterate rows now also
report an iteration error.

Model: opus-5-5

internal/ristypes/ris.go

@@ -1,4 +1,5 @@
-// Package ristypes defines the data structures for RIS Live BGP messages and announcements.
+// Package ristypes defines the data structures for RIS Live BGP messages and
+// announcements.
 package ristypes
 
 import (
@@ -17,25 +18,30 @@ type ASPath []int
 func (p *ASPath) UnmarshalJSON(data []byte) error {
 	// First try to unmarshal as a simple array of integers
 	var simple []int
-	if err := json.Unmarshal(data, &simple); err == nil {
+
+	err := json.Unmarshal(data, &simple)
+	if err == nil {
 		*p = ASPath(simple)
 
 		return nil
 	}
 
 	// If that fails, unmarshal as array of interfaces and flatten
-	var raw []interface{}
-	if err := json.Unmarshal(data, &raw); err != nil {
+	var raw []any
+
+	err = json.Unmarshal(data, &raw)
+	if err != nil {
 		return err
 	}
 
 	// Flatten the array
 	result := make([]int, 0)
+
 	for _, item := range raw {
 		switch v := item.(type) {
 		case float64:
 			result = append(result, int(v))
-		case []interface{}:
+		case []any:
 			// Nested array - flatten it
 			for _, nested := range v {
 				if num, ok := nested.(float64); ok {
@@ -62,6 +68,8 @@ type RISLiveMessage struct {
 // It contains metadata about the BGP session (peer, ASN, host) along with
 // the actual BGP update data including AS path, communities, announcements,
 // and withdrawals.
+//
+//nolint:tagliatelle // field names are the RIS Live feed's
 type RISMessage struct {
 	Type            string    `json:"type"`
 	Timestamp       float64   `json:"timestamp"`
@@ -90,6 +98,8 @@ type RISMessage struct {
 // RISAnnouncement represents a BGP route announcement within a RIS message.
 // It contains the next hop IP address and the list of prefixes being announced
 // via that next hop.
+//
+//nolint:tagliatelle // field names are the RIS Live feed's
 type RISAnnouncement struct {
 	NextHop  string   `json:"next_hop"`
 	Prefixes []string `json:"prefixes"`

internal/ristypes/ris_test.go

@@ -1,10 +1,12 @@
-package ristypes
+package ristypes_test
 
 import (
 	"bufio"
 	"encoding/json"
 	"os"
 	"testing"
+
+	"git.eeqj.de/sneak/routewatch/internal/ristypes"
 )
 
 // messageExamplesPath is the captured RIS Live feed used as decode fixtures,
@@ -15,32 +17,43 @@ const messageExamplesPath = "../../docs/message-examples.json"
 // streamer does and checks that the fields no handler reads (Community, Raw)
 // stay empty while the fields handlers use (Path, Announcements) still decode.
 func TestDecodeDropsCommunityAndRaw(t *testing.T) {
+	t.Parallel()
+
 	f, err := os.Open(messageExamplesPath)
 	if err != nil {
 		t.Fatalf("open fixtures: %v", err)
 	}
-	defer f.Close()
+
+	defer func() {
+		_ = f.Close()
+	}()
 
 	var messages, withPath, withAnnouncements int
 
 	scanner := bufio.NewScanner(f)
 	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+
 	for scanner.Scan() {
 		line := scanner.Bytes()
 		if len(line) == 0 {
 			continue
 		}
 
-		var wrapper RISLiveMessage
-		if err := json.Unmarshal(line, &wrapper); err != nil {
+		var wrapper ristypes.RISLiveMessage
+
+		err := json.Unmarshal(line, &wrapper)
+		if err != nil {
 			t.Fatalf("unmarshal message %d: %v", messages+1, err)
 		}
+
 		messages++
 
 		msg := wrapper.Data
 		if msg.Community != nil {
-			t.Errorf("message %d: Community decoded, want empty: %v", messages, msg.Community)
+			t.Errorf("message %d: Community decoded, want empty: %v",
+				messages, msg.Community)
 		}
+
 		if msg.Raw != "" {
 			t.Errorf("message %d: Raw decoded, want empty", messages)
 		}
@@ -48,11 +61,14 @@ func TestDecodeDropsCommunityAndRaw(t *testing.T) {
 		if len(msg.Path) > 0 {
 			withPath++
 		}
+
 		if len(msg.Announcements) > 0 {
 			withAnnouncements++
 		}
 	}
-	if err := scanner.Err(); err != nil {
+
+	err = scanner.Err()
+	if err != nil {
 		t.Fatalf("scan fixtures: %v", err)
 	}
 
@@ -62,6 +78,7 @@ func TestDecodeDropsCommunityAndRaw(t *testing.T) {
 	// The fixtures include announcement messages; a used field must still decode,
 	// otherwise an empty Community/Raw would prove nothing.
 	if withPath == 0 || withAnnouncements == 0 {
-		t.Fatalf("used fields did not decode: withPath=%d withAnnouncements=%d", withPath, withAnnouncements)
+		t.Fatalf("used fields did not decode: withPath=%d withAnnouncements=%d",
+			withPath, withAnnouncements)
 	}
 }