fix(scraper): replace browserless with direct HTTP and fix presign 404 race

- Fix audio presign 404: MinIO upload is now synchronous before response is sent,
  eliminating the race where presign was called before the file landed in MinIO
- Replace all Browserless usage with direct HTTP client across catalogue, metadata,
  ranking, and browse — novelfire.net pages are server-rendered and don't need a
  headless browser; direct is faster and more reliable
- Harden handleBrowse with 3-attempt retry loop, proper backoff, and full
  browser-like headers to reduce 502s from novelfire.net bot detection
- Remove Browserless env vars (BROWSERLESS_URL/TOKEN/STRATEGY) from main.go;
  add SCRAPER_TIMEOUT as a single timeout knob
- Clean up now-dead rejectResourceTypes var and Browserless-specific WaitFor/
  RejectResourceTypes/GotoOptions fields from scraper calls

scraper/cmd/scraper/main.go

@@ -78,26 +78,16 @@ func run(log *slog.Logger) error {
 
 	cmd := strings.ToLower(args[0])
 
-	browserCfg := browser.Config{
-		BaseURL: envOr("BROWSERLESS_URL", "http://localhost:3030"),
-		Token:   envOr("BROWSERLESS_TOKEN", ""),
-	}
-	browserCfg.MaxConcurrent = 5
-	if s := os.Getenv("BROWSERLESS_MAX_CONCURRENT"); s != "" {
+	// All scraping uses direct HTTP — novelfire.net pages are server-rendered
+	// and do not require a headless browser. A direct HTTP client is faster,
+	// more reliable, and has no Browserless dependency.
+	directCfg := browser.Config{MaxConcurrent: 5}
+	if s := os.Getenv("SCRAPER_TIMEOUT"); s != "" {
 		if n, err := strconv.Atoi(s); err == nil && n > 0 {
-			browserCfg.MaxConcurrent = n
+			directCfg.Timeout = time.Duration(n) * time.Second
 		}
 	}
-	if s := os.Getenv("BROWSERLESS_TIMEOUT"); s != "" {
-		if n, err := strconv.Atoi(s); err == nil && n > 0 {
-			browserCfg.Timeout = time.Duration(n) * time.Second
-		}
-	}
-
-	strategy := browser.Strategy(strings.ToLower(envOr("BROWSERLESS_STRATEGY", string(browser.StrategyDirect))))
-	bc := newBrowserClient(strategy, browserCfg)
-	// Chapter list and chapter text are server-rendered on novelfire.net — direct HTTP for both.
-	directClient := browser.NewDirectHTTPClient(browserCfg)
+	directClient := browser.NewDirectHTTPClient(directCfg)
 
 	// ── Storage backends ────────────────────────────────────────────────────
 	minioCfg := storage.MinioConfig{
@@ -125,7 +115,7 @@ func run(log *slog.Logger) error {
 		return fmt.Errorf("storage init failed: %w", err)
 	}
 
-	nf := novelfire.New(bc, log, directClient, directClient, store)
+	nf := novelfire.New(directClient, log, directClient, directClient, store)
 
 	workers := 0
 	if s := os.Getenv("SCRAPER_WORKERS"); s != "" {
@@ -149,9 +139,8 @@ func run(log *slog.Logger) error {
 			oCfg.SingleBookURL = args[2]
 		}
 		log.Info("starting one-shot scrape",
-			"strategy", strategy,
+			"strategy", "direct",
 			"workers", workers,
-			"max_concurrent", browserCfg.MaxConcurrent,
 			"single_book", oCfg.SingleBookURL,
 			"pocketbase_url", pbCfg.BaseURL,
 			"pocketbase_email", pbCfg.AdminEmail,
@@ -191,9 +180,8 @@ func run(log *slog.Logger) error {
 		kokoroVoice := envOr("KOKORO_VOICE", "af_bella")
 		log.Info("starting HTTP server",
 			"addr", addr,
-			"strategy", strategy,
+			"strategy", "direct",
 			"workers", workers,
-			"max_concurrent", browserCfg.MaxConcurrent,
 			"kokoro_url", kokoroURL,
 			"kokoro_voice", kokoroVoice,
 			"pocketbase_url", pbCfg.BaseURL,
@@ -533,19 +521,6 @@ func downloadAndStoreCoverCLI(store storage.Store, log *slog.Logger, key, imageU
 	log.Debug("save-browse: cover stored", "key", key, "bytes", len(data))
 }
 
-func newBrowserClient(strategy browser.Strategy, cfg browser.Config) browser.BrowserClient {
-	switch strategy {
-	case browser.StrategyScrape:
-		return browser.NewScrapeClient(cfg)
-	case browser.StrategyCDP:
-		return browser.NewCDPClient(cfg)
-	case browser.StrategyDirect:
-		return browser.NewDirectHTTPClient(cfg)
-	default:
-		return browser.NewContentClient(cfg)
-	}
-}
-
 func envOr(key, fallback string) string {
 	if v := os.Getenv(key); v != "" {
 		return v