feat: packages, services and updates

The write side NetOrk/netork#799 needs, on both drivers.

- Packages: get_packages (FreeBSD `pkg query` with the repository as
  source, nothing on a classic system without pkg; OpenBSD `pkg_info`),
  install_package / uninstall_package as root (`pkg install`/`pkg
  delete`, `pkg_add -I`/`pkg_delete`), names checked before anything is
  sent, a failure raised with what the tool printed.
- Updates: get_available_updates. FreeBSD `pkg upgrade -n`, with
  `security` from VuXML (`pkg audit`: True for a listed package, False for
  any other, None when the audit could not run); OpenBSD `pkg_add -u -n
  -v` (no security verdict). Base-system patches are one `base-system`
  entry, as decided in #799: OpenBSD's `syspatch -c`, and on a classic
  FreeBSD what `freebsd-update` has fetched; on pkgbase the base system is
  packages from FreeBSD-base.
- Services: get_services lists the enabled ones (FreeBSD `service ...
  status` as root, as root-only pidfiles hide daemons otherwise, without
  root when sudo refuses; OpenBSD `rcctl check`), manage_service runs
  start/stop/restart/enable/disable as root and returns success and
  output.

Fixtures recorded on the FreeBSD 15.1 and OpenBSD 7.9 VMs with genuinely
outdated packages (FreeBSD pointed at the latest branch, an OpenBSD
package taken back to its release build). Checked live on both, including
a service restart and installing and removing a package.

tests/fixtures/openbsd-vm/pkg_info_full.txt

@@ -0,0 +1,84 @@
+argon2-20190702p0   C implementation of Argon2 - password hashing function
+bash-5.3.9          GNU Bourne Again Shell
+bash-completion-2.17.0 programmable completion functions for bash
+bzip2-1.0.8p0       block-sorting file compressor, unencumbered
+e2fsprogs-1.47.3    utilities to manipulate ext2 filesystems
+gettext-runtime-1.0 GNU gettext runtime libraries and programs
+glib2-2.86.5        general-purpose utility library
+libb2-0.98.1v0      library providing BLAKE2b, BLAKE2s, BLAKE2bp, BLAKE2sp
+libffi-3.5.2p0      Foreign Function Interface
+libiconv-1.19       character set conversion library
+libyaml-0.2.5       YAML 1.1 parser and emitter written in C
+meson-1.10.2v0      next-generation build system
+ninja-1.11.1p1v1    small build system with a focus on speed
+pcre2-10.44         perl-compatible regular expression library, version 2
+py3-MarkupSafe-3.0.3p0 implements an XML/HTML/XHTML markup safe string
+py3-apipkg-3.0.2p1  namespace control and lazy-import mechanism for Python
+py3-argon2-cffi-25.1.0 argon2 password hashing for Python
+py3-argon2-cffi-bindings-25.1.0 argon2 password hashing for Python
+py3-arrow-1.4.0p0   better dates and times for Python
+py3-attrs-25.4.0    classes without boilerplate
+py3-bcrypt-5.0.0p0  bcrypt blowfish password hashing for Python
+py3-blinker-1.9.0p0 fast, simple object-to-object and broadcast signaling
+py3-brotli-1.2.0    Python bindings for the Brotli compression library
+py3-cachetools-7.0.5 extensible memoizing collections and decorators
+py3-certifi-2026.1.4 TLS CA support for Python, patched to use /etc/ssl/cert.pem
+py3-cffi-2.0.0p0    Foreign Function Interface for Python calling C code
+py3-chardet-5.2.0v0 character encoding auto-detection in Python
+py3-charset-normalizer-3.4.7 character set detector library
+py3-colorama-0.4.6p1 print colored terminal text from Python apps
+py3-configobj-5.0.9p0 config file reader and writer
+py3-coverage-7.13.2 code coverage measurement for Python
+py3-cparser-3.0     C parser in pure Python
+py3-cryptography-46.0.7 cryptographic recipes and primitives for Python
+py3-dateutil-2.9.0pl0p0 Python API for advanced date calculations
+py3-distlib-0.4.0   distribution utilities
+py3-execnet-2.1.2   rapid multi-Python deployment
+py3-filelock-3.25.2 platform independent file lock
+py3-fqdn-1.5.1p1    validates that domain names are acceptable to browsers
+py3-idna-3.11       Python library to support the IDNA protocol
+py3-iniconfig-2.3.0 brain-dead simple config-ini parsing
+py3-isoduration-20.11.0p2 operations with ISO 8601 durations
+py3-jinja2-3.1.6p0  fast, optionally sandboxed, Python template engine
+py3-jsonpatch-1.33p2 library to apply JSON Patches according to RFC 6902
+py3-jsonpointer-2.4p2 library to resolve JSON Pointers according to RFC 6901
+py3-jsonschema-4.24.0 implementation of JSON Schema validation for Python
+py3-jsonschema-specifications-2025.4.1 JSON schema meta-schemas and vocabularies
+py3-jwt-2.10.1      JSON Web Token implementation in Python
+py3-mock-5.1.0p0    python mocking and patching library for testing
+py3-oauthlib-3.3.1  Python library for OAuth
+py3-packaging-26.0  core utilities for Python packaging
+py3-passlib-1.9.3p0 Python module providing a password hashing framework
+py3-platformdirs-4.9.6 determine appropriate platform-specific directories
+py3-pluggy-1.6.0p0  plugin and hook calling mechanisms for Python
+py3-pygments-2.20.0 Python syntax highlighter
+py3-pyproject_api-1.10.0 API to interact with pyproject.toml-based projects
+py3-python-discovery-1.2.1p0 library for discovering Python interpreters
+py3-referencing-0.37.0p0 JSON referencing in Python
+py3-requests-2.33.1 elegant and simple HTTP library for Python
+py3-responses-0.25.0p2 utility library for mocking out the `requests` Python
+py3-rfc3339-validator-0.1.4p2 pure python RFC3339 validator
+py3-rfc3986-validator-0.1.1p2 pure python RFC3986 validator
+py3-rpds-py-0.30.0p0 Python bindings for Rust's persistent data structures (rpds)
+py3-scrypt-0.9.4    support for the scrypt key derivation function
+py3-serial-3.5p0    serial interface class for Python
+py3-six-1.17.0p1    Python 2 and 3 compatibility library
+py3-test-9.0.2p0    cross-project testing tool for Python
+py3-test-cov-7.1.0  pytest plugin for measuring coverage
+py3-test-mock-3.15.1 thin wrapper around mock package for easier use with pytest
+py3-test-xdist-3.8.0 py.test xdist plugin for distributed testing
+py3-tox-4.47.0      virtualenv-based automation of test activities
+py3-types-python-dateutil-2.9.0.20260305 typing stubs for Python dateutil
+py3-tzdata-2026.3   IANA timezone data
+py3-uri-template-1.3.0p1 RFC 6570 URI template processor
+py3-urllib3-1.26.20p0 HTTP library for Python
+py3-virtualenv-21.2.3 virtual Python environment builder
+py3-webcolors-25.10.0p0 library for working with HTML color formats
+py3-yaml-6.0.2p1    YAML parser and emitter in Python
+python-3.13.15p0    interpreted object-oriented programming language
+qemu-ga-10.2.1      QEMU guest agent
+quirks-7.194        exceptions to pkg_add rules
+sqlite3-3.51.3      embedded SQL implementation
+sudo-1.9.17.2p1     execute a command as another user
+updatedb-0p0        pkg_add speed up cache
+xz-5.8.4            library and tools for XZ and LZMA compressed files