feat(interval): add bounded package policy features

[kim-em]

Summary

• add a package-agnostic companion registry for versioned integer policy features
• decorate immutable engine offers in deterministic offer/provider/local order while retaining the exact full base offer for freshness checks
• bound accepted provider count, provider checks, features, keys, values, bytes, and pairs; reject duplicate, mismatched, or oversized output transactionally
• test unrelated providers plus same-ID field mutation, duplicate, oversize, ordering, mismatched-limit, zero-limit, and resource failures

Design boundary

This PR does not choose a scoring formula or let feature providers authorize transitions or influence proof evidence. Accepted output is bounded, while callback CPU and candidate-array allocation remain explicitly non-preemptible.

Validation

• focused PolicyFeature, adaptive/staged-policy, exact-branch, subtraction, nested-branch, and complete LogTables conformance build
• trust surface, factor freshness, PNT source inventory, diff, and banned-proof checks