Add readiness probe to devenv

devenv.nix

@@ -85,9 +85,16 @@ in
     '';
     # Waits for postgres's own readiness probe (pg_isready + SELECT 1), not just process start.
     after = [ "devenv:processes:postgres" ];
+    # torad speaks gRPC over a Unix socket and does not register reflection,
+    # so grpcurl would need proto files. Instead use the `tora health` CLI
+    # (already knows the proto, reads TORAD_SOCKET env), which exits 0 iff
+    # torad reports SERVING. torad's poll_db_health flips the status to
+    # NotServing when postgres ping fails, so this also gates on a live DB.
+    ready.exec = "${config.outputs.tora}/bin/tora health";
   };
 
   outputs = {
     torad = cargoNix.workspaceMembers.torad.build;
+    tora = cargoNix.workspaceMembers.tora.build;
   };
 }