Expand the bounded LTP slice with focused socket syscall cases and sync the Makefile, perf runner, syscall matrix, and AI usage disclosure.

Verification via scripts/perf_baseline_runner.py:

1. riscv64 ltp: results/20260630-2221-riscv64-ltp-01, ltp-glibc/musl 159 cases, zero 0, closed true.

2. loongarch64 ltp: results/20260630-2228-loongarch64-ltp-01, ltp-glibc/musl 159 cases, zero 0, closed true.

3. riscv64 all: results/20260630-2235-riscv64-all-01, required groups status ok and closed true.

4. loongarch64 all: results/20260630-2252-loongarch64-all-01, required groups status ok and closed true.

AI-assisted usage: OpenAI Codex / GPT-5 assisted with repository/code reading, verification command execution, result summarization, documentation wording, and commit note drafting. Final code changes, validation, commit, and push were confirmed by the team.