fix: rebase onto main, add IRC wire handlers and integration tests for Tier 3 commands

Rebase onto main to resolve conflicts from module path rename
(sneak.berlin/go/neoirc) and integration test addition.

- Update import paths in utility.go to new module path
- Add IRC wire protocol handlers for VERSION, ADMIN, INFO,
  TIME, KILL, and WALLOPS to ircserver/commands.go
- Register all 6 new commands in the IRC command dispatch map
- Implement proper user MODE +w/-w support for WALLOPS
- Add WALLOPS relay delivery in relay.go
- Add integration tests for all 7 Tier 3 commands:
  USERHOST, VERSION, ADMIN, INFO, TIME, KILL, WALLOPS
- Add newTestEnvWithOper helper for oper-dependent tests

internal/ircserver/server_test.go

@@ -112,6 +112,87 @@ func newTestEnv(t *testing.T) *testEnv {
 	}
 }
 
+// newTestEnvWithOper creates a test environment with oper
+// credentials configured.
+func newTestEnvWithOper(t *testing.T) *testEnv {
+	t.Helper()
+
+	dsn := fmt.Sprintf(
+		"file:%s?mode=memory&cache=shared&_journal_mode=WAL",
+		t.Name(),
+	)
+
+	conn, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		t.Fatalf("open db: %v", err)
+	}
+
+	conn.SetMaxOpenConns(1)
+
+	_, err = conn.ExecContext(
+		t.Context(), "PRAGMA foreign_keys = ON",
+	)
+	if err != nil {
+		t.Fatalf("pragma: %v", err)
+	}
+
+	database := db.NewTestDatabaseFromConn(conn)
+
+	err = database.RunMigrations(t.Context())
+	if err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	brk := broker.New()
+
+	cfg := &config.Config{ //nolint:exhaustruct
+		ServerName:   "test.irc",
+		MOTD:         "Welcome to test IRC",
+		OperName:     "testoper",
+		OperPassword: "testpass",
+	}
+
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+
+	addr := listener.Addr().String()
+
+	err = listener.Close()
+	if err != nil {
+		t.Fatalf("close listener: %v", err)
+	}
+
+	log := slog.New(slog.NewTextHandler(
+		os.Stderr,
+		&slog.HandlerOptions{Level: slog.LevelError}, //nolint:exhaustruct
+	))
+
+	srv := ircserver.NewTestServer(log, cfg, database, brk)
+
+	err = srv.Start(addr)
+	if err != nil {
+		t.Fatalf("start irc server: %v", err)
+	}
+
+	t.Cleanup(func() {
+		srv.Stop()
+
+		err := conn.Close()
+		if err != nil {
+			t.Logf("close db: %v", err)
+		}
+	})
+
+	return &testEnv{
+		database: database,
+		brk:      brk,
+		cfg:      cfg,
+		srv:      srv,
+	}
+}
+
 // dial connects to the test server.
 func (env *testEnv) dial(t *testing.T) *testClient {
 	t.Helper()