fix: close the six defects an independent review found in the trial fixes

Independent read-only review of c56f852..2d29966 (2026-10-08), each defect
reproduced by the reviewer; each new test fails on that code.

- test-lock green ran ANY allowlisted command: `green --cmd "git status"`
  marked a red step green and the stop guard let it stop. The lock now
  stores the step's test command (`lock --cmd`); `green` runs only that
  one (a different --cmd, or a lock without one, exits 2). trekexecute D1
  calls `green` with no command, which also removes the quoting hazard.
- plan-gate --accept-open worked at round 1 and passed the gate; it now
  refuses while rounds are left.
- findings-schema --repo-root swallowed a following flag, or took a root
  that does not exist, and silently skipped the line check: exit 2.
- brief-review-stamp hashed only the body, so a changed `framing` or
  `research_topics` stayed "current"; it now covers the reviewed
  frontmatter too (only the post-review stamps are left out).
- red-proof red_kind read an assertion message naming SyntaxError as a
  load error; the signatures are now specific.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/fixtures/jsonl-schemas.md

@@ -22,7 +22,7 @@
 | trekbrief-stats | ts, task, slug, mode, interview_turns, review_iterations, brief_quality, research_topics, auto_research, auto_result, intent_approved, project_dir, order_id, order_claimed_at, order_reason | commands/trekbrief.md (orchestrator-emit Phase 7; order_* added by lib/stats/stats-append.mjs) | trekbrief.md:1124-1139 | profile, phase_models, profile_source | none |
 | trekresearch-stats | ts, question, mode, scope, engine, slug, project_dir, brief_path, dimensions, dimensions_baseline, dimensions_baseline_preserved, effort, conv_turns, empty_turns, unique_sources, agents_local, agents_external, gemini_used, confidence, contradictions, open_questions | lib/stats/stats-append.mjs (trekresearch.md Stats tracking) | trekresearch.md:782-808 | profile, phase_models, parallel_agents, external_research_enabled, profile_source | none |
 | trekplan-stats | ts, task, mode, slug, brief_path, project_dir, codebase_size, codebase_files, agents_deployed, deep_dives, research_briefs_used, research_scout_used, critic_verdict, guardian_verdict, outcome | lib/stats/stats-append.mjs (trekplan.md Phase 12) | trekplan.md:1115-1135 | profile, phase_models, parallel_agents, profile_source | none |
-| trekexecute-stats (Phase 9 record) | ts, plan, plan_type, mode, result, steps_total, steps_passed, steps_failed, steps_skipped, failed_at_step | lib/stats/stats-append.mjs (trekexecute.md Phase 9) | trekexecute.md:2341-2363 | profile, phase_models, profile_source | none |
+| trekexecute-stats (Phase 9 record) | ts, plan, plan_type, mode, result, steps_total, steps_passed, steps_failed, steps_skipped, failed_at_step | lib/stats/stats-append.mjs (trekexecute.md Phase 9) | trekexecute.md:2343-2365 | profile, phase_models, profile_source | none |
 | trekexecute-stats (autonomy events) | ts, event, known_event, payload | lib/stats/event-emit.mjs `emit()` | event-emit.mjs:78-99 | payload.profile, payload.phase_models, payload.profile_source | none |
 | trekexecute-stats (PostToolUse Bash) | ts, session_id, command_excerpt, duration_ms, success | hooks/scripts/post-bash-stats.mjs (Bash PostToolUse) | post-bash-stats.mjs:42-54 | none (hook is plugin-level, not profile-aware) | command_excerpt (CWE-212) |
 | trekreview-stats | ts, slug, verdict, counts (BLOCKER/MAJOR/MINOR/SUGGESTION), reviewed_files_count, mode, duration_ms | lib/stats/stats-append.mjs (trekreview.md Phase 8) | trekreview.md:628-632 | profile, phase_models, profile_source | none |