Leader Election Generator

[GenerateLeaderElection] creates a typed LeaderElection<TContext> factory and a candidate factory from callback methods.

[GenerateLeaderElection(typeof(WarehouseWorkerContext), ElectionName = "warehouse-replenishment-leader")]
public static partial class WarehouseLeader
{
    [LeaderCandidateId]
    private static string CandidateId(WarehouseWorkerContext context) => context.NodeId;

    [LeaderAcquired]
    private static void Acquired(LeaderLease lease, WarehouseWorkerContext context) { }
}

Diagnostics:

• PKLE001: host type must be partial.
• PKLE002: exactly one candidate id selector is required.
• PKLE003: candidate id or callback signature is invalid.
• PKLE004: lease duration must be positive.