fix: golangci-lint v2 config and lint-clean production code

- Fix .golangci.yml for v2 format (linters-settings -> linters.settings)
- All production code now passes golangci-lint with zero issues
- Line length 88, funlen 80/50, cyclop 15, dupl 100
- Extract shared helpers in db (scanChannels, scanInt64s, scanMessages)
- Split runMigrations into applyMigration/execMigration
- Fix fanOut return signature (remove unused int64)
- Add fanOutSilent helper to avoid dogsled
- Rewrite CLI code for lint compliance (nlreturn, wsl_v5, noctx, etc)
- Rename CLI api package to chatapi to avoid revive var-naming
- Fix all noinlineerr, mnd, perfsprint, funcorder issues
- Fix db tests: extract helpers, add t.Parallel, proper error checks
- Broker tests already clean
- Handler integration tests still have lint issues (next commit)

internal/broker/broker_test.go

@@ -1,20 +1,26 @@
-package broker
+package broker_test
 
 import (
 	"sync"
 	"testing"
 	"time"
+
+	"git.eeqj.de/sneak/chat/internal/broker"
 )
 
 func TestNewBroker(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	if b == nil {
 		t.Fatal("expected non-nil broker")
 	}
 }
 
 func TestWaitAndNotify(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	ch := b.Wait(1)
 
 	go func() {
@@ -30,16 +36,21 @@ func TestWaitAndNotify(t *testing.T) {
 }
 
 func TestNotifyWithoutWaiters(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	b.Notify(42) // should not panic
 }
 
 func TestRemove(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	ch := b.Wait(1)
 	b.Remove(1, ch)
 
 	b.Notify(1)
+
 	select {
 	case <-ch:
 		t.Fatal("should not receive after remove")
@@ -48,7 +59,9 @@ func TestRemove(t *testing.T) {
 }
 
 func TestMultipleWaiters(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	ch1 := b.Wait(1)
 	ch2 := b.Wait(1)
 
@@ -59,6 +72,7 @@ func TestMultipleWaiters(t *testing.T) {
 	case <-time.After(time.Second):
 		t.Fatal("ch1 timeout")
 	}
+
 	select {
 	case <-ch2:
 	case <-time.After(time.Second):
@@ -67,15 +81,23 @@ func TestMultipleWaiters(t *testing.T) {
 }
 
 func TestConcurrentWaitNotify(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
+
 	var wg sync.WaitGroup
 
-	for i := 0; i < 100; i++ {
+	const concurrency = 100
+
+	for i := range concurrency {
 		wg.Add(1)
+
 		go func(uid int64) {
 			defer wg.Done()
+
 			ch := b.Wait(uid)
 			b.Notify(uid)
+
 			select {
 			case <-ch:
 			case <-time.After(time.Second):
@@ -88,7 +110,9 @@ func TestConcurrentWaitNotify(t *testing.T) {
 }
 
 func TestRemoveNonexistent(t *testing.T) {
-	b := New()
+	t.Parallel()
+
+	b := broker.New()
 	ch := make(chan struct{}, 1)
 	b.Remove(999, ch) // should not panic
 }