fix: wire import chapter ingestion, live task polling, a11y labels, notification user targeting

- NewBookImporter now takes *Store instead of raw *minio.Client (same package access)
- Runner Dependencies gains ChapterIngester interface; storeImportedChapters no-op removed
- store.IngestChapters is now actually called after PDF/EPUB extraction
- BookImport and ChapterIngester wired in runner main.go
- CreateImportTask interface gains initiatorUserID param; threaded through store/asynq/handler
- domain.ImportTask gains InitiatorUserID field; parseImportTask populates it
- Runner notifies initiator (falls back to 'admin' when empty)
- UI: import task list polls every 3s while any task is pending/running
- UI: label[for] + input[id] fix for a11y warnings in admin import page

backend/internal/storage/import.go

@@ -1,7 +1,6 @@
 package storage
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -10,7 +9,7 @@ import (
 	"strings"
 
 	"github.com/libnovel/backend/internal/bookstore"
-	"github.com/minio/minio-go/v7"
+	minio "github.com/minio/minio-go/v7"
 )
 
 var (
@@ -18,12 +17,12 @@ var (
 )
 
 type importer struct {
-	mc *minio.Client
+	mc *minioClient
 }
 
 // NewBookImporter creates a BookImporter that reads files from MinIO.
-func NewBookImporter(mc *minio.Client) bookstore.BookImporter {
-	return &importer{mc: mc}
+func NewBookImporter(s *Store) bookstore.BookImporter {
+	return &importer{mc: s.mc}
 }
 
 func (i *importer) Import(ctx context.Context, objectKey, fileType string) ([]bookstore.Chapter, error) {
@@ -31,7 +30,7 @@ func (i *importer) Import(ctx context.Context, objectKey, fileType string) ([]bo
 		return nil, fmt.Errorf("unsupported file type: %s", fileType)
 	}
 
-	obj, err := i.mc.GetObject(ctx, "imports", objectKey, minio.GetObjectOptions{})
+	obj, err := i.mc.client.GetObject(ctx, "imports", objectKey, minio.GetObjectOptions{})
 	if err != nil {
 		return nil, fmt.Errorf("get object from minio: %w", err)
 	}
@@ -142,23 +141,4 @@ func (s *Store) IngestChapters(ctx context.Context, slug string, chapters []book
 // GetImportObjectKey returns the MinIO object key for an uploaded import file.
 func GetImportObjectKey(filename string) string {
 	return fmt.Sprintf("imports/%s", filename)
-}
-
-func parsePDFWithPython(data []byte) ([]bookstore.Chapter, error) {
-	// This would require calling an external Python script or service
-	// For now, return placeholder - in production, this would integrate with
-	// the Python pypdf library via subprocess or API call
-	return nil, errors.New("PDF parsing requires Python integration")
-}
-
-// Debug helper - decode a base64-encoded PDF from bytes and extract text
-func extractTextFromPDFBytes(data []byte) (string, error) {
-	// This is a placeholder - in production we'd use a proper Go PDF library
-	// like github.com/ledongthuc/pdf or the Python approach
-	var buf bytes.Buffer
-	_, err := buf.Write(data)
-	if err != nil {
-		return "", err
-	}
-	return "", errors.New("PDF text extraction not implemented in Go")
 }