Re-vendor the canonical files from sneak/prompts at dd4027b (closes #112)

The shared files are fetched from sneak/prompts dd4027b, with this
repository's own entries after the shared content in .gitignore,
.editorconfig and .dockerignore.

Lint and tests are Dockerfile phases (golangci-lint v2.14.0, Debian Go
1.24.13) that the build stage depends on, and the Makefile targets call
the script/ entrypoints. make fmt also formats Markdown with prettier.

Fixes for the new lint findings: the auth cookie is always Secure, an
IRC connection's relay goroutine stops when the connection closes, and
repeated strings are constants. neoirc-cli treats a plain-HTTP server on
localhost or a loopback address as secure, so local use keeps its session.

Whether the 60-second test cap covers building the test phase is open
on sneak/prompts issue 113.

Model: opus-5-5

internal/service/service.go

@@ -19,6 +19,12 @@ import (
 	"sneak.berlin/go/neoirc/pkg/irc"
 )
 
+// Error texts that several commands reply with.
+const (
+	msgNoSuchChannel = "No such channel"
+	msgNotChannelOp  = "You're not channel operator"
+)
+
 // Params defines the dependencies for creating a Service.
 type Params struct {
 	fx.In
@@ -142,7 +148,7 @@ func (s *Service) SendChannelMessage(
 		return 0, "", &IRCError{
 			irc.ErrNoSuchChannel,
 			[]string{channel},
-			"No such channel",
+			msgNoSuchChannel,
 		}
 	}
 
@@ -256,10 +262,11 @@ func (s *Service) JoinChannel(
 	isCreator := countErr == nil && memberCount == 0
 
 	if !isCreator {
-		if joinErr := checkJoinRestrictions(
+		joinErr := checkJoinRestrictions(
 			ctx, s.db, chID, sessionID,
 			channel, suppliedKey, memberCount,
-		); joinErr != nil {
+		)
+		if joinErr != nil {
 			return nil, joinErr
 		}
 	}
@@ -306,7 +313,7 @@ func (s *Service) PartChannel(
 		return &IRCError{
 			irc.ErrNoSuchChannel,
 			[]string{channel},
-			"No such channel",
+			msgNoSuchChannel,
 		}
 	}
 
@@ -348,7 +355,7 @@ func (s *Service) SetTopic(
 		return &IRCError{
 			irc.ErrNoSuchChannel,
 			[]string{channel},
-			"No such channel",
+			msgNoSuchChannel,
 		}
 	}
 
@@ -372,14 +379,13 @@ func (s *Service) SetTopic(
 			return &IRCError{
 				irc.ErrChanOpPrivsNeeded,
 				[]string{channel},
-				"You're not channel operator",
+				msgNotChannelOp,
 			}
 		}
 	}
 
-	if setErr := s.db.SetTopic(
-		ctx, channel, topic,
-	); setErr != nil {
+	setErr := s.db.SetTopic(ctx, channel, topic)
+	if setErr != nil {
 		return fmt.Errorf("set topic: %w", setErr)
 	}
 
@@ -409,7 +415,7 @@ func (s *Service) KickUser(
 		return &IRCError{
 			irc.ErrNoSuchChannel,
 			[]string{channel},
-			"No such channel",
+			msgNoSuchChannel,
 		}
 	}
 
@@ -420,7 +426,7 @@ func (s *Service) KickUser(
 		return &IRCError{
 			irc.ErrChanOpPrivsNeeded,
 			[]string{channel},
-			"You're not channel operator",
+			msgNotChannelOp,
 		}
 	}
 
@@ -609,7 +615,7 @@ func (s *Service) ValidateChannelOp(
 		return 0, &IRCError{
 			irc.ErrNoSuchChannel,
 			[]string{channel},
-			"No such channel",
+			msgNoSuchChannel,
 		}
 	}
 
@@ -620,7 +626,7 @@ func (s *Service) ValidateChannelOp(
 		return 0, &IRCError{
 			irc.ErrChanOpPrivsNeeded,
 			[]string{channel},
-			"You're not channel operator",
+			msgNotChannelOp,
 		}
 	}
 
@@ -682,33 +688,28 @@ func (s *Service) SetChannelFlag(
 ) error {
 	switch flag {
 	case 'm':
-		if err := s.db.SetChannelModerated(
-			ctx, chID, setting,
-		); err != nil {
+		err := s.db.SetChannelModerated(ctx, chID, setting)
+		if err != nil {
 			return fmt.Errorf("set moderated: %w", err)
 		}
 	case 't':
-		if err := s.db.SetChannelTopicLocked(
-			ctx, chID, setting,
-		); err != nil {
+		err := s.db.SetChannelTopicLocked(ctx, chID, setting)
+		if err != nil {
 			return fmt.Errorf("set topic locked: %w", err)
 		}
 	case 'i':
-		if err := s.db.SetChannelInviteOnly(
-			ctx, chID, setting,
-		); err != nil {
+		err := s.db.SetChannelInviteOnly(ctx, chID, setting)
+		if err != nil {
 			return fmt.Errorf("set invite only: %w", err)
 		}
 	case 's':
-		if err := s.db.SetChannelSecret(
-			ctx, chID, setting,
-		); err != nil {
+		err := s.db.SetChannelSecret(ctx, chID, setting)
+		if err != nil {
 			return fmt.Errorf("set secret: %w", err)
 		}
 	case 'n':
-		if err := s.db.SetChannelNoExternal(
-			ctx, chID, setting,
-		); err != nil {
+		err := s.db.SetChannelNoExternal(ctx, chID, setting)
+		if err != nil {
 			return fmt.Errorf(
 				"set no external: %w", err,
 			)