fix: show first progress update immediately instead of waiting for 5%

- Always show the first nonzero progress update so users don't see 0% for
  extended periods on slow downloads or fragment-based downloads
- Keep 5% throttle for subsequent updates to avoid excessive API calls
- Add readProgress summary logging (lines, matches, stderr length)
- Fix progressKeyboard not being updated until progress >= 5%

internal/handler/download.go

@@ -396,6 +396,8 @@ func (h *Handler) runDownload(ctx context.Context, job *domain.DownloadJob) {
 
 	lastProgress := 0.0
 	for upd := range updates {
+		slog.Info("progress update", "pct", upd.Progress, "speed", upd.Speed, "status", upd.Status)
+
 		h.mu.Lock()
 		currentJob := h.activeJobs[job.UserID]
 		h.mu.Unlock()
@@ -419,18 +421,23 @@ func (h *Handler) runDownload(ctx context.Context, job *domain.DownloadJob) {
 			return
 		}
 
-		if upd.Progress-lastProgress >= domain.ProgressThreshold || upd.Status == domain.StatusCompleted {
+		// Always show the first real progress update, then throttle at 5% intervals
+		if upd.Progress > 0 && lastProgress == 0 {
+			lastProgress = upd.Progress
+		} else if upd.Progress-lastProgress < domain.ProgressThreshold && upd.Status != domain.StatusCompleted {
+			continue
+		} else {
 			lastProgress = upd.Progress
-
-			if upd.Progress > domain.QuotaProgressThreshold && !job.QuotaApplied && job.FileSize > 0 {
-				job.QuotaApplied = true
-				h.applyQuota(job.UserID, job.FileSize)
-			}
-
-			kb := progressKeyboard(upd.Progress, upd.Speed, upd.ETA)
-			text := fmt.Sprintf("Downloading: %s", job.Title)
-			h.editText(ctx, job.ChatID, job.MessageID, text, &kb)
 		}
+
+		if upd.Progress > domain.QuotaProgressThreshold && !job.QuotaApplied && job.FileSize > 0 {
+			job.QuotaApplied = true
+			h.applyQuota(job.UserID, job.FileSize)
+		}
+
+		kb := progressKeyboard(upd.Progress, upd.Speed, upd.ETA)
+		text := fmt.Sprintf("Downloading: %s", job.Title)
+		h.editText(ctx, job.ChatID, job.MessageID, text, &kb)
 	}
 
 	h.mu.Lock()