docs(research): capture direct Copilot sandbox ptrace probe results

[Copilot]

Motivation

Capture a direct, non-inferred ptrace compatibility experiment from the GitHub Copilot coding-agent sandbox, limited to research/, with exact environment facts and probe outcomes.

• Problem summary

  • Run research/ptrace-environment-probe.c in this agent environment, record host/runtime security context and exact probe PASS/FAIL/errno + exit status lines, and document whether the exec-boundary primitives probe exists on origin/main (without recreating it).

• What changed

  • Added direct-run results report
    • New file: research/copilot-coding-agent-ptrace-results.md
    • Includes exact captures for:
      • uname -a
      • /etc/os-release
      • id
      • CapEff, NoNewPrivs, Seccomp from /proc/self/status
      • kernel.yama.ptrace_scope readability and value
      • cgroup/container hints
      • full probe output and exact compile/run exit statuses
  • Exec-boundary primitive probe handling
    • Explicitly documents that research/ptrace-exec-injection-primitives-probe.c is absent on origin/main; no file was recreated.

• Representative snippet

  traceme+exec+regset            result=PASS errno=0 (none) SIGTRAP exec-stop
  seize-sibling                  result=FAIL errno=1 (Operation not permitted) same UID
  seize-sibling-pr-set-ptracer   result=PASS errno=0 (none) target opted in
  probe_exit_status=0
  

Original prompt

Run a direct ptrace compatibility experiment inside this GitHub Copilot coding-agent environment. Work only in research/; do not change product code or workflows. Compile research/ptrace-environment-probe.c with gcc -O2 -Wall -Wextra -Werror and run the resulting binary as the ordinary agent user. Capture uname -a, /etc/os-release, id, CapEff/NoNewPrivs/Seccomp from /proc/self/status, kernel.yama.ptrace_scope when readable, cgroup/container hints, and the complete probe output. Do not infer success: record exact exit status and exact PASS/FAIL/errno lines. Also exercise the exec-boundary injection primitive probe if research/ptrace-exec-injection-primitives-probe.c exists on the base branch; if it is absent, say so rather than recreating it. Write a concise report to research/copilot-coding-agent-ptrace-results.md, clearly labeling this as a direct run in the Copilot coding-agent sandbox, and commit only that report. If compilation or execution is prohibited, record the exact blocker in that report instead. Do not launch GitHub Actions or delegate to another environment.