Windows wheel installation can fail when the installer launcher uses manifest-only runfiles and its Python dependency imports are absent. Declare the installer as an action tool and resolve patch-ng, installer, and pycross imports from runfiles, using Bazel 9 canonical repository names.

The rules_python prerequisite merged in #63785. This PR is now rebased onto master and contains only the 6-file wheel-installation slice of #63670. Next: #63916 (Python/MSI action runtimes).

Validation: wheel_installer_patch_ng_runfiles_test and wheel_library_tool_runfiles_analysis_test passed on macOS, including Bazel 9 manifest, versioned-repository suffix, and runfiles-directory regression cases. The updated manifest tests failed before the naming fix and passed after it. Formatting passed. Native Windows execution requires CI.