Upgrade macOS to Python 3.13 to match Homebrew

[jwnimmer-tri]

Is your feature request related to a problem? Please describe.

The default python@3 in Homebrew is [email protected] now. Due to #21968 we have been unable to upgrade to it, but soon that issue will be fixed. Using a non-default version is annoying for our users.

Describe the solution you'd like

Once that blocking issue is fixed, we should update our support matrix and packaging scripts to add / use [email protected].

For https://drake.mit.edu/from_binary.html, that means changing our binaries to use 3.13 instead of 3.12. This will be a change to our setup/mac/... scripts.

For https://drake.mit.edu/pip.html, we will start by adding a 3.13 wheel. In our next release (v1.38.0, mid-February) I will announce the mac 3.11 wheels as deprecated, and once the deprecation has timed out we'll stop publishing the mac 3.11 wheels.

Also remember to update https://drake.mit.edu/release_notes/end_of_support.html with the "last release number" details.

Additional context

The prior issue (3.11 => 3.12) was #20294.