server: guard against None snapshots crashing the accept loop

If extract_all() returns None (Dashboard init failure), appending it to
store["records"] would cause _accept_loop to crash with AttributeError on
the next client connection.  Since only OSError was caught, the thread
died permanently — no further clients could join push_clients, so live
broadcasts reached nobody.

- collect.py: skip None snapshots instead of appending them
- network.py: filter None records in _accept_loop; catch all exceptions
  during history send (not just OSError) so the thread survives
- storage_helpers.py: filter None records when loading from disk

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

server/collect.py

@@ -49,7 +49,7 @@ def run(args: argparse.Namespace) -> None:
     push_clients, push_lock, push_store_ref = network.start_push_server(args.host, args.port)
     push_store_ref["preloaded"] = load_last_24h_records(logs_dir, vin)
     for _r in push_store_ref["preloaded"]:
-        if "procedural" not in _r:
+        if _r is not None and "procedural" not in _r:
             apply_procedural(_r)
     if push_store_ref["preloaded"]:
         log.info("Pre-loaded %d record(s) from the last 24 h", len(push_store_ref["preloaded"]))
@@ -57,7 +57,7 @@ def run(args: argparse.Namespace) -> None:
     current_day = datetime.now(timezone.utc).date()
     store = load_store(out, vin, args.interval)
     for _r in store["records"]:
-        if "procedural" not in _r:
+        if _r is not None and "procedural" not in _r:
             apply_procedural(_r)
     push_store_ref["current"] = store
     last_broadcast: dict = {}
@@ -86,6 +86,9 @@ def run(args: argparse.Namespace) -> None:
                 try:
                     we_connect.update(wc)
                     snapshot = extract_all(vehicle)
+                    if snapshot is None:
+                        log.warning("extract_all returned None — skipping this cycle")
+                        continue
                     snapshot = apply_procedural(snapshot)
                     store["records"].append(snapshot)
                     save_store(out, store, args.max_records)