refactor(ranking): replace blob cache with per-item PocketBase storage

- Replace SetRanking/GetRanking/SetRankingPageHTML/GetRankingPageHTML blob methods
  with WriteRankingItem/ReadRankingItems/RankingFreshEnough per-item operations
- Add 24h staleness gate in ScrapeRanking to skip re-scraping fresh data
- Add GET /api/ranking endpoint returning []RankingItem sorted by rank
- Remove RankingPageCacher interface and rankingCacheAdapter adapter
- Update integration tests to use new per-item upsert semantics
- Include e2e test suite (scraper/internal/e2e/)

scraper/internal/storage/hybrid.go

@@ -6,7 +6,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -130,43 +129,23 @@ func (h *HybridStore) CountChapters(ctx context.Context, slug string) int {
 
 // ─── Ranking ─────────────────────────────────────────────────────────────────
 
-func (h *HybridStore) WriteRanking(ctx context.Context, items []RankingItem) error {
-	data, err := json.Marshal(items)
-	if err != nil {
-		return fmt.Errorf("storage: marshal ranking: %w", err)
-	}
-	return h.pb.SetRanking(ctx, string(data))
+func (h *HybridStore) WriteRankingItem(ctx context.Context, item RankingItem) error {
+	return h.pb.UpsertRankingItem(ctx, item)
 }
 
 func (h *HybridStore) ReadRankingItems(ctx context.Context) ([]RankingItem, error) {
-	dataStr, _, err := h.pb.GetRanking(ctx)
-	if err != nil || dataStr == "" {
-		return nil, err
+	return h.pb.ListRankingItems(ctx)
+}
+
+func (h *HybridStore) RankingFreshEnough(ctx context.Context, maxAge time.Duration) (bool, error) {
+	last, err := h.pb.RankingLastUpdated(ctx)
+	if err != nil {
+		return false, err
 	}
-	var items []RankingItem
-	if err := json.Unmarshal([]byte(dataStr), &items); err != nil {
-		return nil, fmt.Errorf("storage: unmarshal ranking: %w", err)
+	if last.IsZero() {
+		return false, nil
 	}
-	return items, nil
-}
-
-func (h *HybridStore) RankingFileInfo(ctx context.Context) (os.FileInfo, error) {
-	return h.pb.RankingModTime(ctx)
-}
-
-// ─── Ranking page HTML cache ──────────────────────────────────────────────────
-
-func (h *HybridStore) WriteRankingPageCache(ctx context.Context, page int, html string) error {
-	return h.pb.SetRankingPageHTML(ctx, page, html)
-}
-
-func (h *HybridStore) ReadRankingPageCache(ctx context.Context, page int) (string, error) {
-	html, _, err := h.pb.GetRankingPageHTML(ctx, page)
-	return html, err
-}
-
-func (h *HybridStore) RankingPageCacheInfo(ctx context.Context, page int) (os.FileInfo, error) {
-	return h.pb.RankingPageCacheModTime(ctx, page)
+	return time.Since(last) < maxAge, nil
 }
 
 // ─── Audio cache ──────────────────────────────────────────────────────────────
@@ -222,6 +201,12 @@ func (h *HybridStore) AudioObjectKey(slug string, n int, voice string, speed flo
 	return AudioObjectKey(slug, n, voice, speed)
 }
 
+// ─── PutAudio ─────────────────────────────────────────────────────────────────
+
+func (h *HybridStore) PutAudio(ctx context.Context, key string, data []byte) error {
+	return h.minio.PutAudio(ctx, key, data)
+}
+
 // ─── Presigned URLs ───────────────────────────────────────────────────────────
 
 func (h *HybridStore) PresignChapter(ctx context.Context, slug string, n int, expires time.Duration) (string, error) {
@@ -300,8 +285,11 @@ func splitChapterTitle(raw string) (title, date string) {
 					start = 0
 				}
 				numPart := strings.TrimSpace(raw[start:idx])
-				if _, err := strconv.Atoi(strings.Fields(numPart)[0]); err == nil {
-					return strings.TrimSpace(raw[:start]), strings.TrimSpace(raw[start : idx+len(suffix)])
+				fields := strings.Fields(numPart)
+				if len(fields) > 0 {
+					if _, err := strconv.Atoi(fields[0]); err == nil {
+						return strings.TrimSpace(raw[:start]), strings.TrimSpace(raw[start : idx+len(suffix)])
+					}
 				}
 			}
 		}