feat: add SSR data helpers to library handler

- Add GetUserVisibleLibrariesData() method for server-side rendering
- Add GetLibraryTypeData() method for SSR type fetching
- These helpers return data directly instead of JSON responses
- Enables Hybrid SSR pattern while preserving API endpoints
- Add context import for new methods

internal/handlers/library.go

@@ -3,6 +3,7 @@ package handlers
 import (
 	"bookhoard/internal/database"
 	"bookhoard/internal/services"
+	"context"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -302,3 +303,13 @@ func parseUUID(uuidStr string) (pgtype.UUID, error) {
 	}
 	return pgtype.UUID{Bytes: [16]byte(parsedUUID), Valid: true}, nil
 }
+
+// GetUserVisibleLibrariesData returns libraries for SSR (not JSON response)
+func (h *LibraryHandler) GetUserVisibleLibrariesData(ctx context.Context, userID pgtype.UUID) ([]database.GetUserVisibleLibrariesRow, error) {
+	return h.libraryService.GetUserVisibleLibraries(ctx, userID)
+}
+
+// GetLibraryTypeData returns all library types for SSR (not JSON response)
+func (h *LibraryHandler) GetLibraryTypeData(ctx context.Context) ([]database.LibraryTypes, error) {
+	return h.libraryService.GetLibraryTypes(ctx)
+}