fix: rebase onto main, fix SQLite concurrency, lint clean

- Add busy_timeout PRAGMA and MaxOpenConns(1) for SQLite stability
- Use per-test temp DB in handler tests to prevent state leaks
- Pre-allocate migrations slice (prealloc lint)
- Remove invalid linter names (wsl_v5, noinlineerr) from .golangci.yml
- Remove unused //nolint:gosec directives
- Replace context.Background() with t.Context() in tests
- Use goimports formatting for all files
- All make check passes with zero failures

internal/db/db.go

@@ -81,7 +81,7 @@ func (s *Database) GetDB() *sql.DB {
 func (s *Database) connect(ctx context.Context) error {
 	dbURL := s.params.Config.DBURL
 	if dbURL == "" {
-		dbURL = "file:./data.db?_journal_mode=WAL"
+		dbURL = "file:./data.db?_journal_mode=WAL&_busy_timeout=5000"
 	}
 
 	s.log.Info("connecting to database", "url", dbURL)
@@ -104,6 +104,8 @@ func (s *Database) connect(ctx context.Context) error {
 		return err
 	}
 
+	d.SetMaxOpenConns(1)
+
 	s.db = d
 	s.log.Info("database connected")
 
@@ -114,6 +116,13 @@ func (s *Database) connect(ctx context.Context) error {
 		return fmt.Errorf("enable foreign keys: %w", err)
 	}
 
+	_, err = s.db.ExecContext(
+		ctx, "PRAGMA busy_timeout = 5000",
+	)
+	if err != nil {
+		return fmt.Errorf("set busy timeout: %w", err)
+	}
+
 	return s.runMigrations(ctx)
 }
 
@@ -233,7 +242,7 @@ func (s *Database) loadMigrations() (
 		)
 	}
 
-	var migrations []migration
+	migrations := make([]migration, 0, len(entries))
 
 	for _, entry := range entries {
 		if entry.IsDir() ||

internal/db/queries_test.go

@@ -1,7 +1,6 @@
 package db_test
 
 import (
-	"context"
 	"encoding/json"
 	"testing"
 
@@ -32,7 +31,7 @@ func TestCreateUser(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	id, token, err := database.CreateUser(ctx, "alice")
 	if err != nil {
@@ -53,7 +52,7 @@ func TestGetUserByToken(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	_, token, err := database.CreateUser(ctx, "bob")
 	if err != nil {
@@ -79,7 +78,7 @@ func TestGetUserByNick(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	_, _, err := database.CreateUser(ctx, "charlie")
 	if err != nil {
@@ -101,7 +100,7 @@ func TestChannelOperations(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	chID, err := database.GetOrCreateChannel(ctx, "#test")
 	if err != nil || chID == 0 {
@@ -128,7 +127,7 @@ func TestJoinAndPart(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid, _, err := database.CreateUser(ctx, "user1")
 	if err != nil {
@@ -170,7 +169,7 @@ func TestDeleteChannelIfEmpty(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	chID, err := database.GetOrCreateChannel(
 		ctx, "#empty",
@@ -212,7 +211,7 @@ func createUserWithChannels(
 ) (int64, int64, int64) {
 	t.Helper()
 
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid, _, err := database.CreateUser(ctx, nick)
 	if err != nil {
@@ -255,7 +254,7 @@ func TestListChannels(t *testing.T) {
 	)
 
 	channels, err := database.ListChannels(
-		context.Background(), uid,
+		t.Context(), uid,
 	)
 	if err != nil || len(channels) != 2 {
 		t.Fatalf(
@@ -269,7 +268,7 @@ func TestListAllChannels(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	_, err := database.GetOrCreateChannel(ctx, "#x")
 	if err != nil {
@@ -294,7 +293,7 @@ func TestChangeNick(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid, token, err := database.CreateUser(ctx, "old")
 	if err != nil {
@@ -320,7 +319,7 @@ func TestSetTopic(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	_, err := database.GetOrCreateChannel(
 		ctx, "#topictest",
@@ -354,7 +353,7 @@ func TestInsertAndPollMessages(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid, _, err := database.CreateUser(ctx, "poller")
 	if err != nil {
@@ -415,7 +414,7 @@ func TestGetHistory(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	const msgCount = 10
 
@@ -452,7 +451,7 @@ func TestDeleteUser(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid, _, err := database.CreateUser(ctx, "deleteme")
 	if err != nil {
@@ -491,7 +490,7 @@ func TestChannelMembers(t *testing.T) {
 	t.Parallel()
 
 	database := setupTestDB(t)
-	ctx := context.Background()
+	ctx := t.Context()
 
 	uid1, _, err := database.CreateUser(ctx, "m1")
 	if err != nil {
@@ -539,7 +538,7 @@ func TestGetAllChannelMembershipsForUser(t *testing.T) {
 
 	channels, err :=
 		database.GetAllChannelMembershipsForUser(
-			context.Background(), uid,
+			t.Context(), uid,
 		)
 	if err != nil || len(channels) != 2 {
 		t.Fatalf(

internal/handlers/api_test.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"path/filepath"
 	"strings"
 	"sync"
 	"testing"
@@ -35,6 +36,10 @@ type testServer struct {
 func newTestServer(t *testing.T) *testServer {
 	t.Helper()
 
+	// Use a unique DB per test to avoid SQLite BUSY and state leaks.
+	dbPath := filepath.Join(t.TempDir(), "test.db")
+	t.Setenv("DBURL", "file:"+dbPath+"?_journal_mode=WAL&_busy_timeout=5000")
+
 	var s *server.Server
 
 	app := fxtest.New(t,
@@ -158,7 +163,7 @@ func (ts *testServer) doReq(
 		req.Header.Set("Content-Type", "application/json")
 	}
 
-	return http.DefaultClient.Do(req) //nolint:gosec // test server URL
+	return http.DefaultClient.Do(req)
 }
 
 func (ts *testServer) doReqAuth(
@@ -181,7 +186,7 @@ func (ts *testServer) doReqAuth(
 		req.Header.Set("Authorization", "Bearer "+token)
 	}
 
-	return http.DefaultClient.Do(req) //nolint:gosec // test server URL
+	return http.DefaultClient.Do(req)
 }
 
 func (ts *testServer) createSession(nick string) string {
@@ -984,7 +989,7 @@ func TestConcurrentSessions(t *testing.T) {
 		go func(i int) {
 			defer wg.Done()
 
-			nick := "concurrent_" + string(rune('a'+i)) //nolint:gosec // i is 0-19, safe range
+			nick := "concurrent_" + string(rune('a'+i))
 
 			body, err := json.Marshal(map[string]string{"nick": nick})
 			if err != nil {