[tools] Default to C++23 on Noble

Author: jwnimmer-tri

doc/_pages/installation.md

@@ -60,7 +60,7 @@ Drake's pre-compiled binaries:
 | Operating System                   | C/C++ Compiler             | Std   |
 |------------------------------------|----------------------------|-------|
 | Ubuntu 22.04 LTS (Jammy Jellyfish) | GCC 11                     | C++20 |
-| Ubuntu 24.04 LTS (Noble Numbat)    | GCC 13                     | C++20 |
+| Ubuntu 24.04 LTS (Noble Numbat)    | GCC 13                     | C++23 |
 | macOS Sonoma (14)                  | Apple LLVM 16 (Xcode 16.2) | C++20 |
 | macOS Sequoia (15)                 | Apple LLVM 17 (Xcode 16.4) | C++20 |
 

tools/ubuntu-noble.bazelrc

@@ -1,3 +1,7 @@
+# Use C++23 on Noble.
+build --cxxopt=-std=c++23
+build --host_cxxopt=-std=c++23
+
 # Options for explicitly using Clang.
 # Keep this in sync with doc/_pages/from_source.md.
 common:clang --repo_env=CC=clang-19