Cut over prediction research and retire duplicate loop state

[proerror77]

Parent

#184

Depends on

#202, #203, and deterministic/cloud parity evidence for both adapters.

Change contract

After deterministic and cloud parity evidence, remove the active duplicate prediction LoopRun and Alpha Search MCTS state paths so only the shared controller can advance a research mission in either lane.

Acceptance evidence

• A fixed snapshot and mission produce matching baseline reports and an explainable, versioned search-result comparison.
• Crash/resume and budget exhaustion are proven through the official entrypoint.
• Legacy checkpoint input is either explicitly migrated once or rejected fail-closed; it is never silently reinterpreted.
• Source and CLI searches show one active owner for MCTS budget, checkpoint, backpropagation, and terminal state in each lane.
• The retired paths and tests are deleted rather than layered behind permanent compatibility flags.

Out of scope

Collector/data/snapshot changes, result-object publication owned by #170, evaluator redesign, Paper/Live, OMS, or RiskGate.

Rollout/rollback

Cutover uses an immutable image and one named controller. Rollback uses the prior image and prior checkpoint schema; mixed writers are forbidden.