Build a governor pause/resume control surface

[JSONbored]

Problem: The governor ledger only logs decisions after the fact — the actual pause capability it would need to enforce doesn't exist yet at all, not just the UI for it.

Area: AMS / Miner

Proposal: Build a real pause/resume mechanism the governor (and an operator directly) can invoke, that the loop actually checks before proceeding.

Deliverables:

• A working pause/resume flag, checked by the loop before each iteration, controllable via CLI.

Acceptance criteria:

• Pausing mid-run stops further iterations; resuming continues from where it left off.

Boundaries:

• This builds the mechanism only — the actual autonomous governor logic that decides when to pause is Miner Wave 3's scope, tracked separately.

[linear-code]

JSO-3511