Add batch commands to PortTracker CLI and migrate batch tables into porting.db

Implements batch list/show/ready/next/start/complete commands with dependency
validation, migrates 42 implementation batches (2377 features, 2087 tests) from
porting_batches.db into the live tracking database, and documents the batch
workflow in AGENTS.md.

tools/NatsNet.PortTracker/Program.cs

@@ -41,6 +41,7 @@ rootCommand.Add(ReportCommands.Create(dbOption, schemaOption));
 rootCommand.Add(PhaseCommands.Create(dbOption, schemaOption));
 rootCommand.Add(AuditCommand.Create(dbOption));
 rootCommand.Add(OverrideCommands.Create(dbOption));
+rootCommand.Add(BatchCommands.Create(dbOption));
 
 var parseResult = rootCommand.Parse(args);
 return await parseResult.InvokeAsync();