[P2-E6.2] Cadence parametrization + validation rules

**Context.** FR-27 says "a parametrized timeframe": the reporting window is network
config, not operator choice. Late/missing reports are themselves signals.

**Deliverable.** Window length as config (AmuletConfig or per-sync governance state);
on-ledger validation of window bounds against the config; staleness definition (a sync
whose last report is > N windows old is "silent") queryable.

**Acceptance.** Config change adjusts accepted windows; overdue detection exercised in
test.

**Depends on.** P2-E6.1.

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Epic: #69 · Plan: [P2-E6-consumption-reporting.md](https://github.com/ChainSafe/canton-extending-mainnet/blob/main/docs/planning/phase-2-epics/P2-E6-consumption-reporting.md)

Read the linked P2-E6-consumption-reporting.md plan and the prerequisite P2-E6.1 issue first. Locate AmuletConfig or the per-sync governance state, then trace the existing reporting validation and query paths. Done means configuration changes adjust accepted windows and tests exercise overdue or silent-sync detection.

Written by the indexing model from the issue text.