Add copyright headers to Python binding files (partial)

This commit adds or updates copyright headers for several files
related to the new Python bindings. The year is set to 2025,
and "Jules <jules@google.com> (Google AI Agent)" is added as an
author. The license is GPL-2.0+.

Files updated so far:

• configure.ac (author added, year confirmed)
• libnozzle/bindings/python/Makefile.am (year updated, author added)
• libnozzle/bindings/python/_nozzle.c (new header added)
• libnozzle/bindings/python/tests/__init__.py (new one-line header)
• libnozzle/bindings/python/tests/test_nozzle.py (new header, corrected position after shebang)
• libknet/bindings/python/Makefile.am (year updated, author added)
• libknet/bindings/python/_knet.c (new header added)
• libknet/bindings/python/tests/__init__.py (new one-line header)

I was interrupted before completing updates for all planned files.
Specifically, libknet/bindings/python/tests/test_knet.py still
needs its copyright header added.

Throughout this task, I've been unable to run any build commands
(autogen.sh, configure, make) due to persistent internal errors.
This has prevented any compilation or testing of the bindings
and their integration into the build system. The changes made
are based on static analysis of the codebase and adherence to
existing patterns.