feat: add TimeSlave process and libTSClient shm IPC channel

[gordon9901]

feat: introduce TimeSlave process and libTSClient IPC channel

Summary

This PR splits the gPTP protocol stack out of TimeDaemon into a new standalone process — TimeSlave — and introduces a lightweight shared-memory IPC library (libTSClient) so that TimeDaemon can consume PtpTimeInfo snapshots from TimeSlave without running the raw-socket protocol itself.

Changes

score/TimeSlave/ (new) A self-contained gPTP slave process (score::ts::TimeSlave) that:

• Runs GptpEngine (existing RxThread + PdelayThread logic) to participate in IEEE 802.1AS protocol.
• Includes platform implementations for both Linux and QNX (raw_socket, network_identity, phc_adjuster).
• Exposes instrumentation (probe) and recording (recorder) capabilities.
• Publishes PtpTimeInfo snapshots to shared memory via GptpIpcPublisher.

score/libTSClient/ (new) A process-boundary IPC library providing:

• GptpIpcRegion — 64-byte cache-line-aligned shared memory layout with a seqlock (seq / seq_confirm) for lock-free single-writer / multi-reader access.
• GptpIpcPublisher — creates and writes to the POSIX shared memory segment (used by TimeSlave).
• GptpIpcReceiver — opens and reads from the segment with seqlock retry (used by TimeDaemon via RealPTPEngine).

score/TimeDaemon/code/ptp_machine/real/ (new)

• RealPTPEngine — a PTPEngine-compatible adapter backed by GptpIpcReceiver.
• GPTPRealMachine — type alias for PTPMachine<RealPTPEngine>, slotting cleanly into the existing TimeDaemon pipeline.
• CreateGPTPRealMachine() — factory function for convenient construction.

score/TimeDaemon/code/common/BUILD, data_types/BUILD (modified) Widened Bazel visibility from //score/TimeDaemon:__subpackages__ to //score:__subpackages__ so that TimeSlave and libTSClient can reuse shared data types (PtpTimeInfo, etc.) without duplication.

score/TimeDaemon/code/ptp_machine/BUILD (modified) Added //score/TimeDaemon/code/ptp_machine/real:unit_test_suite to the aggregated test target.

Architecture

TimeSlave (new process)
  └── GptpEngine (RxThread + PdelayThread)
        └── GptpIpcPublisher  ──[POSIX shm / seqlock]──►  GptpIpcReceiver
                                                                 └── RealPTPEngine
                                                                       └── GPTPRealMachine
                                                                             └── TimeDaemon pipeline

Test Coverage

Component	Line Coverage	Function Coverage
ptp_machine/real	100.0% (3/3)	100.0% (1/1)
ptp_machine/real/details	97.6% (41/42)	100.0% (8/8)
libTSClient	87.2% (68/78)	100.0% (10/10)
TimeSlave/gptp	91.4% (170/186)	100.0% (13/13)
TimeSlave/gptp/details	96.9% (284/293)	87.5% (28/32)
TimeSlave/gptp/instrument	100.0% (21/21)	100.0% (6/6)
TimeSlave/gptp/record	100.0% (22/22)	100.0% (4/4)
Overall	94.4% (609/645)	94.6% (70/74)

Ticket:eclipse-score/score#2691

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run //:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
2026/03/27 06:50:14 Downloading https://releases.bazel.build/8.3.0/release/bazel-8.3.0-linux-x86_64...
Extracting Bazel installation...
Starting local Bazel server (8.3.0) and connecting to it...
INFO: Invocation ID: c1f33f8d-0428-4030-bf53-f4f272c59b17
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
WARNING: For repository 'aspect_rules_lint', the root module requires module version aspect_rules_lint@1.5.3, but got aspect_rules_lint@2.0.0 in the resolved dependency graph. Please update the version in your MODULE.bazel or set --check_direct_dependencies=off
Computing main repo mapping: 
Computing main repo mapping: 
Computing main repo mapping: 
Loading: 
Loading: 2 packages loaded
Loading: 2 packages loaded
    currently loading: 
Loading: 2 packages loaded
    currently loading: 
Loading: 2 packages loaded
    currently loading: 
Loading: 2 packages loaded
    currently loading: 
Analyzing: target //:license-check (3 packages loaded, 0 targets configured)
Analyzing: target //:license-check (3 packages loaded, 0 targets configured)

Analyzing: target //:license-check (27 packages loaded, 9 targets configured)

Analyzing: target //:license-check (73 packages loaded, 9 targets configured)

Analyzing: target //:license-check (88 packages loaded, 9 targets configured)

Analyzing: target //:license-check (91 packages loaded, 9 targets configured)

Analyzing: target //:license-check (148 packages loaded, 2654 targets configured)

Analyzing: target //:license-check (157 packages loaded, 7615 targets configured)

Analyzing: target //:license-check (169 packages loaded, 8037 targets configured)

Analyzing: target //:license-check (169 packages loaded, 8049 targets configured)

Analyzing: target //:license-check (169 packages loaded, 8049 targets configured)

Analyzing: target //:license-check (172 packages loaded, 9937 targets configured)

INFO: Analyzed target //:license-check (174 packages loaded, 10184 targets configured).
[1 / 1] no actions running
[12 / 16] checking cached actions
INFO: From Generating Dash formatted dependency file ...:
INFO: Successfully converted 2 packages from Cargo.lock to bazel-out/k8-fastbuild/bin/formatted.txt
[13 / 16] JavaToolchainCompileClasses external/rules_java+/toolchains/platformclasspath_classes; 0s disk-cache, processwrapper-sandbox
[14 / 16] checking cached actions
[14 / 16] [Prepa] JavaToolchainCompileBootClasspath external/rules_java+/toolchains/platformclasspath.jar
[15 / 16] Building license.check.license_check.jar (); 0s disk-cache, multiplex-worker
INFO: Found 1 target...
Target //:license.check.license_check up-to-date:
  bazel-bin/license.check.license_check
  bazel-bin/license.check.license_check.jar
INFO: Elapsed time: 38.652s, Critical Path: 2.34s
INFO: 16 processes: 12 internal, 3 processwrapper-sandbox, 1 worker.
INFO: Build completed successfully, 16 total actions
INFO: Running command line: bazel-bin/license.check.license_check ./formatted.txt <args omitted>
usage: org.eclipse.dash.licenses.cli.Main [-batch <int>] [-cd <url>]
       [-confidence <int>] [-ef <url>] [-excludeSources <sources>] [-help] [-lic
       <url>] [-project <shortname>] [-repo <url>] [-review] [-summary <file>]
       [-timeout <seconds>] [-token <token>]