Promote uv publish from preview to stable

[konstin]

uv publish is getting adopted and we fix all user reports. We should promote it from preview to stable.

Blocking

Checklist for promoting it to stable:

• Migrate uv from pypa/gh-action-pypi-publish to uv publish: Use uv publish to publish itself #8065
• Create an example repo that use uv to publish a package to pypi and one alternative index: https://github.com/astral-sh/trusted-publishing-examples
• Build and publish from CI complete example #7727
• uv publish times out when uploading large packages (~85MiB) #7809
• [feat] uv publish --skip-existing #7917
• Incorrect documentation for aws code-artifact publication #7958
• Configuring multiple indexes with uv publish #7963 (Documentation)
• uv publish giving Missing credentials for https://upload.pypi.org/legacy/ #8023
• Bug: uv publish missing METADATA file #8030
• uv publish interactive like twine? #8073
• Flakes in uv publish integration test #8418 (the first case, the others are fixed already)
• Private Projects #8214
• uv publish doesn't respect the --allow-insecure-host flag #8423
• Warn when using the keyring in uv publish but it doesn't have credentials #8781
• Publish: Hint at --skip-existing -> --check-url transition #8803
• Bug(?): uv publish fails if unknown files are present in ./dist #8944

(wait one or two releases)

• Promotion PR

Not blocking

These items are part of uv publish, but don't block stabilizing the feature itself.

• Support index declarations in uv publish #8864

Not included

• Test publish::invalid_token flake on Windows #8535 (Internal test flake)
• Equivalent command to twine check #8641 We want this is in some capacity; I expect it to become part of the build backend or part of build build, doing it as part of publish is too late. It's not blocking stabilization.
• Equivalent command to check-wheel-contents #8774 We want this is in some capacity; I expect it to become part of the build backend or part of build build, doing it as part of publish is too late. It's not blocking stabilization.