Add a new HasChannelEdge method that takes a gossip version parameter
and returns only existence and zombie status, without timestamp data.
This supports both v1 and v2 gossip protocols.
The original HasChannelEdge method is renamed to HasV1ChannelEdge to
preserve v1-specific functionality for callers that need timestamp
information. All call sites are updated accordingly.
The SQL store implementation now handles both gossip versions, using
timestamps for v1 and block heights for v2 policies, with proper
reject cache support for both versions.
Elle Mouton
506ec037e2