Context freshness contract

Cross-runtime enum (Rust: ainl_contracts::ContextFreshness; JSON in tooling/ainl_policy_contract.json).

| Value | Meaning | Consumer behavior (strict) | |-------|---------|----------------------------| | fresh | Code/index context is confidently current. | May proceed to execute after normal validation. | | stale | Known mismatch (e.g. index behind HEAD). | Prefer impact / ir_diff before writes; refresh index when possible. | | unknown | Cannot determine from available signals. | Conservative: recommend impact-first chain; do not assume repo-wide safety. |

Default in AINL MCP: unknown — the Python MCP server does not embed git or external indexers; freshness may be supplied by ArmaraOS or future hooks.

Without ainl-inference-server: this contract is still valid; inference-server is optional for planner telemetry only.