Fall back to disk when in-memory store is empty on client connect

storage_helpers: load_today_records() scans logs/ for all files
matching today's UTC date and VIN, merges and sorts their records.

network: _accept_loop receives an optional load_today callable;
if store_ref["current"] has no records it calls load_today() to
replay the day's history from disk before adding the client.

collect: passes a load_today lambda (None when -o is used).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

collect.py

@@ -57,7 +57,7 @@ from pathlib import Path
 
 from server import log_config, network, we_connect
 from server.data_model import ALL_DOMAINS, collect_snapshot
-from server.storage_helpers import auto_out_path, load_store, save_store
+from server.storage_helpers import auto_out_path, load_store, load_today_records, save_store
 
 log = logging.getLogger(__name__)
 
@@ -93,10 +93,14 @@ def run(args: argparse.Namespace) -> None:
         logs_dir.mkdir(exist_ok=True)
         out = auto_out_path(logs_dir, vin)
 
-    push_clients, push_lock, push_last = network.start_push_server(args.host, args.port)
+    load_today = (lambda: load_today_records(logs_dir, vin)) if logs_dir else None
+    push_clients, push_lock, push_store_ref = network.start_push_server(
+        args.host, args.port, load_today=load_today
+    )
 
     current_day = datetime.now(timezone.utc).date()
     store = load_store(out, vin, args.interval)
+    push_store_ref["current"] = store
     log.info(
         "Collecting [%s] every %ds → %s  (Ctrl-C to stop)",
         ", ".join(domains),
@@ -111,6 +115,7 @@ def run(args: argparse.Namespace) -> None:
                 if today != current_day:
                     out = auto_out_path(logs_dir, vin)
                     store = load_store(out, vin, args.interval)
+                    push_store_ref["current"] = store
                     current_day = today
                     log.info("Midnight UTC rotation → %s", out)
 
@@ -119,7 +124,7 @@ def run(args: argparse.Namespace) -> None:
                 snapshot = collect_snapshot(vehicle, domains)
                 store["records"].append(snapshot)
                 save_store(out, store, args.max_records)
-                network.broadcast(snapshot, push_clients, push_lock, push_last)
+                network.broadcast(snapshot, push_clients, push_lock)
                 log.info("Record #%d saved at %s", len(store["records"]), snapshot["ts"])
             except KeyboardInterrupt:
                 raise