refactor: apply go fix modernizers for Go 1.26

Automated fixes: interface{} → any, range-over-int, t.Context(),
wg.Go(), strings.SplitSeq, strings.Builder, slices.Contains,
maps helpers, min/max builtins.

Co-Authored-By: Virgil <virgil@lethean.io>

allowance_redis_test.go

@@ -289,7 +289,7 @@ func TestRedisStore_ConcurrentIncrementUsage_Good(t *testing.T) {
 
 	var wg sync.WaitGroup
 	wg.Add(goroutines)
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			err := s.IncrementUsage("agent-1", tokensEach, 1)
@@ -313,7 +313,7 @@ func TestRedisStore_ConcurrentModelUsage_Good(t *testing.T) {
 
 	var wg sync.WaitGroup
 	wg.Add(goroutines)
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			err := s.IncrementModelUsage("claude-opus-4-6", tokensEach)
@@ -342,7 +342,7 @@ func TestRedisStore_ConcurrentMixed_Good(t *testing.T) {
 	wg.Add(goroutines * 3)
 
 	// Increment usage
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.IncrementUsage("agent-1", 100, 1)
@@ -350,7 +350,7 @@ func TestRedisStore_ConcurrentMixed_Good(t *testing.T) {
 	}
 
 	// Decrement active jobs
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.DecrementActiveJobs("agent-1")
@@ -358,7 +358,7 @@ func TestRedisStore_ConcurrentMixed_Good(t *testing.T) {
 	}
 
 	// Return tokens
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.ReturnTokens("agent-1", 10)

allowance_sqlite_test.go

@@ -282,7 +282,7 @@ func TestSQLiteStore_ConcurrentIncrementUsage_Good(t *testing.T) {
 
 	var wg sync.WaitGroup
 	wg.Add(goroutines)
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			err := s.IncrementUsage("agent-1", tokensEach, 1)
@@ -306,7 +306,7 @@ func TestSQLiteStore_ConcurrentModelUsage_Good(t *testing.T) {
 
 	var wg sync.WaitGroup
 	wg.Add(goroutines)
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			err := s.IncrementModelUsage("claude-opus-4-6", tokensEach)
@@ -335,7 +335,7 @@ func TestSQLiteStore_ConcurrentMixed_Good(t *testing.T) {
 	wg.Add(goroutines * 3)
 
 	// Increment usage
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.IncrementUsage("agent-1", 100, 1)
@@ -343,7 +343,7 @@ func TestSQLiteStore_ConcurrentMixed_Good(t *testing.T) {
 	}
 
 	// Decrement active jobs
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.DecrementActiveJobs("agent-1")
@@ -351,7 +351,7 @@ func TestSQLiteStore_ConcurrentMixed_Good(t *testing.T) {
 	}
 
 	// Return tokens
-	for i := 0; i < goroutines; i++ {
+	for range goroutines {
 		go func() {
 			defer wg.Done()
 			_ = s.ReturnTokens("agent-1", 10)

cmd/tasks/cmd.go

@@ -53,8 +53,8 @@ var (
 
 // task command flags
 var (
-	taskAutoSelect bool
-	taskClaim      bool
+	taskAutoSelect  bool
+	taskClaim       bool
 	taskShowContext bool
 )
 
@@ -236,7 +236,7 @@ func AddTaskCommands(parent *cli.Command) {
 }
 
 func printTaskList(tasks []agentic.Task) {
-	cli.Print("\n%s\n\n", i18n.T("cmd.ai.tasks.found", map[string]interface{}{"Count": len(tasks)}))
+	cli.Print("\n%s\n\n", i18n.T("cmd.ai.tasks.found", map[string]any{"Count": len(tasks)}))
 
 	for _, task := range tasks {
 		id := taskIDStyle.Render(task.ID)

cmd/tasks/updates.go

@@ -101,7 +101,7 @@ var taskCompleteCmd = &cli.Command{
 		})
 
 		if taskCompleteFailed {
-			cli.Print("%s %s\n", errorStyle.Render(">>"), i18n.T("cmd.ai.task_complete.failed", map[string]interface{}{"ID": taskID}))
+			cli.Print("%s %s\n", errorStyle.Render(">>"), i18n.T("cmd.ai.task_complete.failed", map[string]any{"ID": taskID}))
 		} else {
 			cli.Print("%s %s\n", successStyle.Render(">>"), i18n.T("i18n.done.complete", "task"))
 		}

config.go

@@ -101,7 +101,7 @@ func loadEnvFile(path string, cfg *Config) error {
 		return err
 	}
 
-	for _, line := range strings.Split(content, "\n") {
+	for line := range strings.SplitSeq(content, "\n") {
 		line = strings.TrimSpace(line)
 
 		// Skip empty lines and comments

context.go

@@ -142,7 +142,7 @@ func findRelatedCode(task *Task, dir string) ([]FileContent, error) {
 		}
 
 		// Parse matched files
-		for _, line := range strings.Split(output, "\n") {
+		for line := range strings.SplitSeq(output, "\n") {
 			line = strings.TrimSpace(line)
 			if line == "" || seen[line] {
 				continue

context_git_test.go

@@ -79,7 +79,7 @@ func TestFindRelatedCode_Good_NoKeywords(t *testing.T) {
 
 	task := &Task{
 		ID:          "code-2",
-		Title:       "do it",  // too short, all stop words
+		Title:       "do it", // too short, all stop words
 		Description: "fix the bug in the code",
 	}
 
@@ -101,7 +101,7 @@ func TestFindRelatedCode_Good_LimitsTo10Files(t *testing.T) {
 	dir := initGitRepoWithCode(t)
 
 	// Create 15 files all containing the keyword "validation".
-	for i := 0; i < 15; i++ {
+	for i := range 15 {
 		name := filepath.Join(dir, "validation_"+string(rune('a'+i))+".go")
 		content := "package main\n// validation logic\nfunc Validate" + string(rune('A'+i)) + "() {}\n"
 		err := os.WriteFile(name, []byte(content), 0644)

dispatcher_test.go

@@ -257,7 +257,7 @@ func TestDispatcher_Dispatch_Good_Concurrent(t *testing.T) {
 	})
 
 	var wg sync.WaitGroup
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		wg.Add(1)
 		go func(n int) {
 			defer wg.Done()

events_integration_test.go

@@ -271,7 +271,7 @@ func TestAllowanceService_NoEventsWithoutEmitter(t *testing.T) {
 func drainEvents(em *ChannelEmitter, n int, timeout time.Duration) []Event {
 	var events []Event
 	deadline := time.After(timeout)
-	for i := 0; i < n; i++ {
+	for range n {
 		select {
 		case e := <-em.Events():
 			events = append(events, e)

events_test.go

@@ -119,12 +119,10 @@ func TestChannelEmitter_ConcurrentEmit(t *testing.T) {
 	ctx := context.Background()
 
 	var wg sync.WaitGroup
-	for i := 0; i < 50; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+	for range 50 {
+		wg.Go(func() {
 			_ = em.Emit(ctx, Event{Type: EventTaskDispatched})
-		}()
+		})
 	}
 	wg.Wait()
 

lifecycle_test.go

@@ -237,7 +237,7 @@ func TestTaskLifecycle_MultipleAgentsConcurrent(t *testing.T) {
 		wg.Add(1)
 		go func(aid string) {
 			defer wg.Done()
-			for i := 0; i < 10; i++ {
+			for range 10 {
 				// Check allowance.
 				result, err := svc.Check(aid, "")
 				assert.NoError(t, err)
@@ -268,9 +268,9 @@ func TestTaskLifecycle_MultipleAgentsConcurrent(t *testing.T) {
 	for _, agentID := range agents {
 		usage, err := store.GetUsage(agentID)
 		require.NoError(t, err)
-		assert.Equal(t, int64(1500), usage.TokensUsed)  // 10 jobs x 150 tokens
-		assert.Equal(t, 10, usage.JobsStarted)           // 10 starts
-		assert.Equal(t, 0, usage.ActiveJobs)              // all completed
+		assert.Equal(t, int64(1500), usage.TokensUsed) // 10 jobs x 150 tokens
+		assert.Equal(t, 10, usage.JobsStarted)         // 10 starts
+		assert.Equal(t, 0, usage.ActiveJobs)           // all completed
 	}
 }
 

registry_redis_test.go

@@ -275,7 +275,7 @@ func TestRedisRegistry_Concurrent_Good(t *testing.T) {
 	reg := newTestRedisRegistry(t)
 
 	var wg sync.WaitGroup
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		wg.Add(1)
 		go func(n int) {
 			defer wg.Done()

registry_sqlite_test.go

@@ -280,7 +280,7 @@ func TestSQLiteRegistry_Concurrent_Good(t *testing.T) {
 	reg := newTestSQLiteRegistry(t)
 
 	var wg sync.WaitGroup
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		wg.Add(1)
 		go func(n int) {
 			defer wg.Done()

registry_test.go

@@ -273,7 +273,7 @@ func TestMemoryRegistry_Concurrent_Good(t *testing.T) {
 	reg := NewMemoryRegistry()
 
 	var wg sync.WaitGroup
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		wg.Add(1)
 		go func(n int) {
 			defer wg.Done()

types.go

@@ -56,7 +56,7 @@ type Task struct {
 	// CreatedAt is when the task was created.
 	CreatedAt time.Time `json:"created_at"`
 	// UpdatedAt is when the task was last modified.
-	UpdatedAt time.Time `json:"updated_at,omitempty"`
+	UpdatedAt time.Time `json:"updated_at"`
 	// ClaimedBy is the identifier of the agent or developer who claimed the task.
 	ClaimedBy string `json:"claimed_by,omitempty"`
 	// ClaimedAt is when the task was claimed.