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>

benchmark_test.go

@@ -15,9 +15,9 @@ func generateMarkdownDoc() string {
 	sb.WriteString("# Benchmark Document\n\n")
 	sb.WriteString("This document is generated for benchmarking the chunking pipeline.\n\n")
 
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		sb.WriteString(fmt.Sprintf("## Section %d\n\n", i+1))
-		for j := 0; j < 5; j++ {
+		for j := range 5 {
 			sb.WriteString(fmt.Sprintf(
 				"Paragraph %d in section %d contains representative text for testing. "+
 					"It includes multiple sentences to exercise the sentence-aware splitter. "+
@@ -76,7 +76,7 @@ func BenchmarkQuery_Mock(b *testing.B) {
 	store := newMockVectorStore()
 	store.collections["bench-col"] = 768
 	// Pre-populate with 50 points
-	for i := 0; i < 50; i++ {
+	for i := range 50 {
 		store.points["bench-col"] = append(store.points["bench-col"], Point{
 			ID:     fmt.Sprintf("p%d", i),
 			Vector: make([]float32, 768),
@@ -106,7 +106,7 @@ func BenchmarkQuery_Mock(b *testing.B) {
 func BenchmarkIngest_Mock(b *testing.B) {
 	dir := b.TempDir()
 	// Create 10 markdown files
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		content := fmt.Sprintf("## File %d\n\nThis is file number %d with some test content for benchmarking.\n", i, i)
 		path := filepath.Join(dir, fmt.Sprintf("doc%d.md", i))
 		if err := os.WriteFile(path, []byte(content), 0644); err != nil {

chunk_test.go

@@ -217,7 +217,7 @@ func TestChunkMarkdown_Edge_VeryLongSingleParagraph(t *testing.T) {
 	t.Run("long paragraph with line breaks produces chunks", func(t *testing.T) {
 		// Create long text with paragraph breaks so chunking can split
 		var parts []string
-		for i := 0; i < 50; i++ {
+		for range 50 {
 			parts = append(parts, "This is paragraph number that contains some meaningful text for testing purposes.")
 		}
 		longText := "## Long Content\n\n" + joinParagraphs(parts)
@@ -331,23 +331,23 @@ func TestDefaultIngestConfig(t *testing.T) {
 
 // Helper: repeat a string n times
 func repeatString(s string, n int) string {
-	result := ""
-	for i := 0; i < n; i++ {
-		result += s
+	var result strings.Builder
+	for range n {
+		result.WriteString(s)
 	}
-	return result
+	return result.String()
 }
 
 // Helper: join paragraphs with double newlines
 func joinParagraphs(parts []string) string {
-	result := ""
+	var result strings.Builder
 	for i, p := range parts {
 		if i > 0 {
-			result += "\n\n"
+			result.WriteString("\n\n")
 		}
-		result += p
+		result.WriteString(p)
 	}
-	return result
+	return result.String()
 }
 
 // --- Phase 3.1: Sentence splitting and overlap alignment ---

helpers_test.go

@@ -32,7 +32,7 @@ func TestQueryWith(t *testing.T) {
 
 	t.Run("respects topK parameter", func(t *testing.T) {
 		store := newMockVectorStore()
-		for i := 0; i < 10; i++ {
+		for i := range 10 {
 			store.points["col"] = append(store.points["col"], Point{
 				ID:     fmt.Sprintf("p%d", i),
 				Vector: []float32{0.1},

ingest.go

@@ -160,10 +160,7 @@ func Ingest(ctx context.Context, store VectorStore, embedder Embedder, cfg Inges
 	// Batch upsert to vector store
 	if len(points) > 0 {
 		for i := 0; i < len(points); i += cfg.BatchSize {
-			end := i + cfg.BatchSize
-			if end > len(points) {
-				end = len(points)
-			}
+			end := min(i+cfg.BatchSize, len(points))
 			batch := points[i:end]
 			if err := store.UpsertPoints(ctx, cfg.Collection, batch); err != nil {
 				return stats, log.E("rag.Ingest", fmt.Sprintf("error upserting batch %d", i/cfg.BatchSize+1), err)

ingest_test.go

@@ -47,7 +47,7 @@ func TestIngest(t *testing.T) {
 		// Create content large enough to produce multiple chunks
 		var content string
 		content = "## Big Section\n\n"
-		for i := 0; i < 30; i++ {
+		for i := range 30 {
 			content += fmt.Sprintf("Paragraph %d with some meaningful content for testing. ", i)
 			if i%3 == 0 {
 				content += "\n\n"
@@ -187,7 +187,7 @@ func TestIngest(t *testing.T) {
 	t.Run("batch size handling — multiple batches", func(t *testing.T) {
 		dir := t.TempDir()
 		// Create enough content for multiple chunks
-		for i := 0; i < 5; i++ {
+		for i := range 5 {
 			writeFile(t, filepath.Join(dir, fmt.Sprintf("doc%d.md", i)),
 				fmt.Sprintf("## Section %d\n\nContent for document %d.\n", i, i))
 		}

qdrant.go

@@ -170,7 +170,7 @@ func (q *QdrantClient) Search(ctx context.Context, collection string, vector []f
 	query := &qdrant.QueryPoints{
 		CollectionName: collection,
 		Query:          qdrant.NewQuery(vector...),
-		Limit:          qdrant.PtrOf(limit),
+		Limit:          new(limit),
 		WithPayload:    qdrant.NewWithPayload(true),
 	}
 

query_test.go

@@ -493,7 +493,7 @@ func TestQuery(t *testing.T) {
 	t.Run("results respect limit", func(t *testing.T) {
 		store := newMockVectorStore()
 		// Add many points
-		for i := 0; i < 10; i++ {
+		for i := range 10 {
 			store.points["test-col"] = append(store.points["test-col"], Point{
 				ID:     fmt.Sprintf("p%d", i),
 				Vector: []float32{0.1},