snapshot() Method Returns Shallow Copies

[CyberSecDef]

Problem

novelforge/progress.py lines 184-190: snapshot() returns shallow copies while get() returns deep copies. Nested structures in returned entries are shared references to the internal store.

Why It Matters

Code using snapshot() could inadvertently mutate the internal store by modifying nested data, contradicting the safety guarantee established by get().

Recommended Fix

def snapshot(self) -> dict[str, ProgressState]:
    with self._lock:
        return {k: copy.deepcopy(v) for k, v in self._store.items()}