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.
Make the reject cache version-aware so v1 and v2 policy state can be
cached independently per channel ID. Add helpers to store v1 timestamps
or v2 block heights and thread the versioned cache key through KV/SQL
store cache accesses.
Elle Mouton