feat(runtime): policy engine for autonomous lane management

rust/crates/runtime/src/lib.rs

@@ -14,6 +14,7 @@ mod mcp_stdio;
 pub mod mcp_tool_bridge;
 mod oauth;
 pub mod permission_enforcer;
+mod policy_engine;
 mod permissions;
 mod prompt;
 mod remote;
@@ -76,6 +77,10 @@ pub use oauth::{
     OAuthCallbackParams, OAuthRefreshRequest, OAuthTokenExchangeRequest, OAuthTokenSet,
     PkceChallengeMethod, PkceCodePair,
 };
+pub use policy_engine::{
+    evaluate, DiffScope, GreenLevel, LaneBlocker, LaneContext, PolicyAction, PolicyCondition,
+    PolicyEngine, PolicyRule, ReviewStatus,
+};
 pub use permissions::{
     PermissionContext, PermissionMode, PermissionOutcome, PermissionOverride, PermissionPolicy,
     PermissionPromptDecision, PermissionPrompter, PermissionRequest,