feat(pipeline) Redesign orchestrator pipeline

[manjari25]

Summary

feat(pipeline) Redesign orchestrator pipeline

New orchestator pipeline set up in this PR as described in the table below -

Controller	Subscribes From	Publishes To	Entity In	Entity Out
request	request	validate	Request	Request
validate	validate	batch	Request	Request
batch	batch	score	Request	Batch
score	score	speculate	Batch	Batch
speculate	speculate	build, merge	Batch	Batch
build	build	buildsignal	Batch	Build
buildsignal	buildsignal	speculate	Build	Batch
merge	merge	conclude, speculate	Batch	Batch
conclude	conclude	—	Batch	—

What?

• Redesign the orchestrator queue pipeline as described in the table above
• Add 3 new pipeline stage controllers: validate (request validation and merge checks), score
  (batch scoring before speculation) and conclude (pipeline finalization)
• Rename 2 controllers: mergesignal, and finalize
• Update existing controllers (batch, build, merge, speculate, buildsignal) to operate on proper domain entities
  (e.g., build controller now consumes Batch and produces Build instead of passing Request through)
• Move merge conflict check from request controller to validate controller
• Add Build.ToBytes()/BuildFromBytes() serialization for queue transport of build entities
• Rename topic keys in TopicRegistry to match the new stage names
• Log message updates to indicate which exact pipeline a controller is publishing to
• Register new controllers in orchestrator server

Why?

• This scaffolds the orchestrator pipeline and sets up controllers needed to process a land request.

Test Plan

Unit tests added and updated.

Issues