Store: fix NPS refresh, scan race, thread cleanup, and matching perf

app/info.py

@@ -23,6 +23,9 @@ _miss_db = {}
 _miss_loaded = False
 _MISS_TTL = 86400.0  # retry failed metadata after 1 day
 
+# Memoised release-date table (invalidated on save/reset).
+_dates_cache = None
+
 
 def _load_miss_db():
     global _miss_loaded
@@ -122,6 +125,7 @@ def save(release_id, system, meta, manual=False, title=None):
         )
         conn.commit()
         conn.close()
+        _invalidate_dates_cache()
         return True
     except sqlite3.Error:
         return False
@@ -140,6 +144,7 @@ def reset(release_id, system):
         )
         conn.commit()
         conn.close()
+        _invalidate_dates_cache()
     except sqlite3.Error:
         pass
 
@@ -161,23 +166,32 @@ def cached_release_dates():
     """Return {(release_id, system): release_date} from cached metadata only.
 
     Pure DB read — no network — so list views can show a release date without
-    triggering API fetches for every row.
+    triggering API fetches for every row. Result is memoised and invalidated
+    whenever metadata is saved.
     """
-    out = {}
-    try:
-        conn = get_connection(config.DB_PATH)
-        rows = conn.execute("SELECT release_id, system, meta_json FROM item_info").fetchall()
-        conn.close()
-    except sqlite3.Error:
-        return {}
-    for r in rows:
+    global _dates_cache
+    if _dates_cache is None:
+        out = {}
         try:
-            meta = json.loads(r["meta_json"] or "{}")
-        except (TypeError, ValueError):
-            continue
-        if isinstance(meta, dict) and meta.get("release_date"):
-            out[(r["release_id"], r["system"])] = meta["release_date"]
-    return out
+            conn = get_connection(config.DB_PATH)
+            rows = conn.execute("SELECT release_id, system, meta_json FROM item_info").fetchall()
+            conn.close()
+        except sqlite3.Error:
+            return out
+        for r in rows:
+            try:
+                meta = json.loads(r["meta_json"] or "{}")
+            except (TypeError, ValueError):
+                continue
+            if isinstance(meta, dict) and meta.get("release_date"):
+                out[(r["release_id"], r["system"])] = meta["release_date"]
+        _dates_cache = out
+    return _dates_cache
+
+
+def _invalidate_dates_cache():
+    global _dates_cache
+    _dates_cache = None
 
 
 def get_or_fetch(release_id, system, fetch_title):