refactor(server): rewrote cell access using new helpers and added ast-grep rules for it

mise.toml

@@ -10,6 +10,7 @@ protoc = "29.6"
 "cargo:cargo-shear" = "latest"
 "cargo:cargo-insta" = "1.46.3"
 python = "3.14.3"
+ast-grep = "0.42.0"
 
 [tasks.codegen]
 sources = ['protobufs/*.proto']
@@ -17,4 +18,4 @@ outputs = ['useragent/lib/proto/*']
 run = '''
 dart pub global activate protoc_plugin && \
 protoc --dart_out=grpc:useragent/lib/proto --proto_path=protobufs/ protobufs/*.proto
-'''
+'''