feat(material-lifecycle): add Stage-0 contracts

[huangruiteng]

Summary

• add a built-in, default-off, goal-scoped Material Lifecycle capability
• define public-safe inventory, backup-safe migration plan, lifecycle receipt, bounded rerank proposal, and apply receipt contracts
• connect bounded rerank proposals to revisioned Decision Context evidence without coupling to a provider
• expose a read-only architecture CLI, capability catalog entry, bilingual protocol docs, and focused public smokes

Boundary

• raw material, private locations, provider payloads, credentials, and source-store formats never enter public packets
• source snapshots and backups precede dual-read reconciliation; cutover and rollback stay owner-gated
• recurring automation is kept thin: source profiles, cursors, ranking rules, and exploration providers remain deferred
• this PR does not include a legacy parser, migration apply path, web exploration, messaging adapter, or private dogfood data

Validation

• pytest tests/capabilities/test_material_lifecycle_contracts.py tests/capabilities/test_capability_extension_registry.py -q (21 passed)
• python examples/material-lifecycle-contract-smoke.py
• python examples/capability-extension-registry-smoke.py
• Ruff check and format check for the new package/tests/smoke
• risk-based canary premerge --from-git-diff --tier standard: 18/18 selected checks passed, no warnings or manual holds
• public/private boundary scan: 17 files clean

Residual risk

The contracts intentionally precede real storage adapters. The next slice must prove a read-only legacy inventory, stable IDs, exact count reconciliation, and rollback before any source mutation is considered.