ollie-remote: fix empty output and wire generic tool dispatch

Shell results were returned as raw strings but the agent expects
structured content blocks ({content:[{type:text,text:...}]}). Fixed
shell handler to return the same format as the local Server.CallTool.

Shell errors now return as isError content blocks rather than RPC
errors, matching local behavior (output is preserved in errors).

The default RPC handler now dispatches to srv.CallTool() for any
unknown method, enabling named tools (file_read, file_grep, etc.)
from the embedded tools to be called remotely.

cmd/ollie-remote/main.go

@@ -167,13 +167,18 @@ func serveRPC(ctx context.Context, srv *toolsrv.Server, in io.Reader, out io.Wri
 				enc.Encode(rpcResponse{
 					JSONRPC: "2.0",
 					ID:      req.ID,
-					Error:   &rpcError{Code: -32000, Message: err.Error()},
+					Result: map[string]any{
+						"isError": true,
+						"content": []map[string]string{{"type": "text", "text": err.Error()}},
+					},
 				})
 			} else {
 				enc.Encode(rpcResponse{
 					JSONRPC: "2.0",
 					ID:      req.ID,
-					Result:  result,
+					Result: map[string]any{
+						"content": []map[string]string{{"type": "text", "text": result}},
+					},
 				})
 			}
 
@@ -213,11 +218,27 @@ func serveRPC(ctx context.Context, srv *toolsrv.Server, in io.Reader, out io.Wri
 			})
 
 		default:
-			enc.Encode(rpcResponse{
+			// Dispatch to named tool via the tool server's CallTool.
-				JSONRPC: "2.0",
+			streamCtx := toolsrv.WithOutputStream(ctx, func(data string) {
-				ID:      req.ID,
+				enc.Encode(rpcResponse{
-				Error:   &rpcError{Code: -32601, Message: "method not found: " + req.Method},
+					JSONRPC: "2.0",
+					Result:  outputNotif{Data: data},
+				})
 			})
+			result, err := srv.CallTool(streamCtx, req.Method, req.Params)
+			if err != nil {
+				enc.Encode(rpcResponse{
+					JSONRPC: "2.0",
+					ID:      req.ID,
+					Error:   &rpcError{Code: -32000, Message: err.Error()},
+				})
+			} else {
+				enc.Encode(rpcResponse{
+					JSONRPC: "2.0",
+					ID:      req.ID,
+					Result:  json.RawMessage(result),
+				})
+			}
 		}
 	}
 }