Extend ChannelEdgePolicy to support v2 channel updates by adding:
- Version field to track gossip protocol version (v1 or v2).
- LastBlockHeight for v2's block-height-based timestamps.
- SecondPeer flag to indicate which peer announced the policy in v2.
- DisableFlags for v2-specific channel disable signaling.
- ExtraSignedFields map for v2 extra signed TLV data.
Add version-aware methods:
- IsNode1() determines if the policy was announced by node_1, handling
both v1 (via ChannelFlags direction bit) and v2 (via SecondPeer).
- IsDisabled() checks disable status using ChannelFlags for v1 and
DisableFlags for v2.
- String() provides version-appropriate string representations.
The new fields use zero values for v1 compatibility (Version defaults
to GossipVersion1, LastBlockHeight to 0, SecondPeer to false). This
lays the groundwork for v2 policy support; a subsequent commit will
handle reading and writing these fields from/to the database.
Elle Mouton
3fe40c6540