test: add invariant suite for JailingPolicy

[fgimenez]

asana: https://app.asana.com/0/1213822431665320/1214550222776111

Adds Foundry invariant coverage for JailingPolicy, which previously had only unit tests. A JailingHandler drives a single heartbeat round through vote → finalize → recordRound → enforceOne / enforceAll, tracking ghost state for votes, enforcement and timestamps.

Invariants:

• roundRecord is immutable once set and consistent with manager.roundOutcome.
• The number of enforced flags is bounded by committee size and matches the handler's monotonic ghost counter.
• Correct voters (verdict matching outcome) and verdict==3 voters are never enforced.
• Inconclusive outcomes never produce any enforcement.
• Enforced operators remain isJailed for the full jail window after enforcement.
• The recorded committee root matches the manager's stored root.