Smooth rate/ETA over 30-min rolling window instead of single snapshot

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/mosaic_progress_report.py

@@ -202,14 +202,25 @@ def main() -> None:
         except Exception:
             pass
 
+    # Rolling rate: keep up to 60 snapshots; compute rate from the oldest
+    # snapshot within the last 30 minutes for a smoothed estimate.
+    snapshots: list[dict] = cache.get("snapshots", [])
+    # Prune snapshots older than 30 minutes, but keep at least one
+    cutoff = now.timestamp() - 1800
+    recent = [s for s in snapshots if s.get("ts", 0) >= cutoff]
+    if not recent and snapshots:
+        recent = [snapshots[-1]]  # always keep one for continuity
+
     rate_per_sec: float | None = None
-    prev_ts   = _parse_dt(cache.get("timestamp", ""))
-    prev_proc = cache.get("processed")
-    if prev_ts and prev_proc is not None:
-        dt = (now - prev_ts).total_seconds()
-        dp = processed - int(prev_proc)
+    rate_window_str = ""
+    if recent:
+        oldest = recent[0]
+        dt = now.timestamp() - oldest["ts"]
+        dp = processed - oldest["proc"]
         if dt >= 60 and dp > 0:
             rate_per_sec = dp / dt
+            window_min = dt / 60
+            rate_window_str = f"{window_min:.0f}-min avg"
 
     # --- Disk space ---
     mean_bytes: float | None = None
@@ -225,7 +236,10 @@ def main() -> None:
         dl_bytes  = downloaded * mean_bytes
         rem_bytes = _expected_remaining(pending_rows) * mean_bytes
 
-    # Update cache
+    # Update cache: append new snapshot, keep last 60
+    recent.append({"ts": now.timestamp(), "proc": processed})
+    cache["snapshots"] = recent[-60:]
+    # Keep legacy keys for backwards compat
     cache["timestamp"] = now.isoformat()
     cache["processed"] = processed
     try:
@@ -235,7 +249,7 @@ def main() -> None:
 
     rate_str = eta_str = ""
     if rate_per_sec and rate_per_sec > 0:
-        rate_str = f"{rate_per_sec * 3600:,.0f} scans/hr"
+        rate_str = f"{rate_per_sec * 3600:,.0f} scans/hr ({rate_window_str})"
         eta_str  = _fmt_duration(pending / rate_per_sec)
 
     # -----------------------------------------------------------------------