[fjtrujy]

Goal

Extend CI beyond successful compilation and the portable C smoke tests, exercising as much of the existing protocol behavior as possible without physical PS2 hardware or Python.

Changes

• Add a dedicated Ubuntu job that builds the native C fake PS2Link server and runs the full existing Linux tests/run-tests.sh integration suite inside privileged, isolated network namespaces. This checks handshakes, host-file I/O (including large reads), timeouts, disconnects, console output, retries and error exits.
• Run a new native C Windows smoke harness on the Windows matrix worker. It checks invalid host handling, usage errors, the UDP console, and the reset command wire packet.
• Preserve existing macOS (Apple Silicon and Intel), Ubuntu, Windows and cross-Windows builds, plus all existing make check C suites.
• Document running the integration suite locally.

Validation

• macOS make all check: passes C smoke, symbolizer, and fsclient test suites.
• bash -n tests/run-tests.sh and git diff --check: pass.
• Linux namespace and native Windows C execution require CI runners; this PR is intended to prove both paths.

Deliberate limits

Real PS2 behavior and IOP file-I/O internals cannot be executed by the host-side fake. This PR changes only ps2client's test/CI infrastructure, not ps2link itself.

Verified CI results

• 38/38 Linux protocol integration checks passed against the native C fake-PS2Link server using isolated Linux network namespaces.
• 8/8 native Windows C smoke checks passed, including UDP console and reset packet checks.
• Existing macOS/Linux C smoke, symbolizer and fsclient suites passed.
• Codacy: zero new issues on the initial CI run.
• Release publishing now depends on the Linux integration job as well as all build jobs, so a failed protocol test blocks a release.

The dedicated Linux and Windows checks run on GitHub-hosted runners; physical PS2 execution remains intentionally outside this PR.